Organometallic compound and light-emitting device including organometallic compound

ABSTRACT

Provided are an organometallic compound represented by Formula 1, a light-emitting device including the organometallic compound represented by Formula 1, and an electronic apparatus including the light-emitting device:Formula 1 is understood by referring to the description of Formula 1 provided herein.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and benefits of Korean PatentApplication No. 10-2021-0042219 under 35 U.S.C. § 119, filed on Mar. 31,2021 in the Korean Intellectual Property Office, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND 1. Technical Field

Embodiments relate to an organometallic compound, a light-emittingdevice including the organometallic compound, and an electronicapparatus including the light-emitting device.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) among light-emitting devices areself-emissive devices that, as compared with devices in the art, havewide viewing angles, high contrast ratios, short response times, andexcellent characteristics in terms of brightness, driving voltage, andresponse speed.

OLEDs may include a first electrode on a substrate, and a hole transportregion, an emission layer, an electron transport region, and a secondelectrode sequentially stacked on the first electrode. Holes providedfrom the first electrode may move toward the emission layer through thehole transport region, and electrons provided from the second electrodemay move toward the emission layer through the electron transportregion. Carriers, such as holes and electrons, recombine in the emissionlayer to produce excitons. These excitons transition from an excitedstate to a ground state, thereby generating light.

It is to be understood that this background of the technology sectionis, in part, intended to provide useful background for understanding thetechnology. However, this background of the technology section may alsoinclude ideas, concepts, or recognitions that were not part of what wasknown or appreciated by those skilled in the pertinent art prior to acorresponding effective filing date of the subject matter disclosedherein.

SUMMARY

Embodiments include an organometallic compound having a low drivingvoltage, excellent luminescence efficiency, long lifespan, and excellentcolorimetric purity and a light-emitting device including theorganometallic compound.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the embodiments of the disclosure.

According to an embodiment, an organometallic compound may berepresented by Formula 1.

In Formula 1,

M may be platinum (Pt), palladium (Pd), nickel (Ni), copper (Cu), silver(Ag), gold (Au), rhodium (Rh), iridium (Ir), ruthenium (Ru), osmium(Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu),terbium (Tb), or thulium (Tm),

X₁ to X₄ may each independently be carbon (C) or nitrogen (N),

Y₁ may be N,

A₁ to A₄ may each independently be a C₃-C₆₀ carbocyclic group or aC₁-C₆₀ heterocyclic group,

CY₁ may be a C₁-C₆₀ heterocyclic group,

T₁ may be N, B, P, C(Z₁₁), Si(Z₁₁), or Ge(Z₁₁),

T₂ to T₄ may each independently be a single bond, a double bond,*—N(Z₂₁)—*′, *—B(Z₂₁)—*′, *—P(Z₂₁)—*′, *—C(Z₂₁)(Z₂₂)—*′,*—Si(Z₂₁)(Z₂₂)—*′, *—Ge(Z₂₁)(Z₂₂)—*′, *—S—*′, *—Se—*′, *—O—*,*—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(Z₂₁)=*′, *═C(Z₂₁)—*′,*—C(Z₂₁)═C(Z₂₂)—*′, *—C(═S)—*′, or *—C≡C—*′, and * and *′ each indicatea binding site to an adjacent atom,

a2 to a4 may each independently be an integer from 0 to 3,

R₁ to R₅, Z₁₁, Z₂₁, and Z₂₂ may each independently be hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, a C₁-C₆₀ alkyl group unsubstituted or substituted with at leastone R_(10a), a C₂-C₆₀ alkenyl group unsubstituted or substituted with atleast one R_(10a), a C₂-C₆₀ alkynyl group unsubstituted or substitutedwith at least one R_(10a), a C₁-C₆₀ alkoxy group unsubstituted orsubstituted with at least one R_(10a), a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a), a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), a C₆-C₆₀ aryloxy group unsubstituted or substituted with atleast one R_(10a), a C₆-C₆₀ arylthio group unsubstituted or substitutedwith at least one R_(10a), —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂),—C(═O)(Q₁), —S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂),

b1 to b5 may each independently be an integer from 0 to 10,

two R₁(s) of at least two R₁(s) when b1 is 2 or greater may optionallybe bound to each other to form a C₃-C₆₀ carbocyclic group unsubstitutedor substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic groupunsubstituted or substituted with at least one R_(10a), two R₂(s) of atleast two R₂(s) when b2 is 2 or greater may optionally be bound to eachother to form a C₃-C₆₀ carbocyclic group unsubstituted or substitutedwith at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstitutedor substituted with at least one R_(10a), two R₃(s) of at least twoR₃(s) when b3 is 2 or greater may optionally be bound to each other toform a C₃-C₆₀ carbocyclic group unsubstituted or substituted with atleast one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted orsubstituted with at least one R_(10a), two R₄(s) of at least two R₄(s)when b4 is 2 or greater may optionally be bound to each other to form aC₃-C₆₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), two R₅(s) of at least two R₅(s) when b5 is 2 orgreater are optionally bound to each other to form a C₃-C₆₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), and

R_(10a) may be

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or a nitrogroup,

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, ora C₁-C₆₀ alkoxy group, each unsubstituted or substituted with deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, aC₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂),—B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), —P(═O)(Q₁₁)(Q₁₂), or anycombination thereof,

a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀aryloxy group, or a C₆-C₆₀ arylthio group, each unsubstituted orsubstituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group,a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthiogroup, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁),—S(═O)₂(Q₂₁), —P(═O)(Q₂₁)(Q₂₂), or any combination thereof, or

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), or —P(═O)(Q₃₁)(Q₃₂),

wherein Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may eachindependently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, or aC₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group, eachunsubstituted or substituted with deuterium, —F, a cyano group, a C₁-C₆₀alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl group, orany combination thereof, and

* and *′ each indicate a binding site to an adjacent atom.

In an embodiment, a bond between X₁ and M may be a covalent bond, a bondbetween X₂ and M may be a covalent bond, a bond between X₃ and M may bea coordinate bond, and a bond between X₄ and M may be a covalent bond ora coordinate bond.

In an embodiment, A₃ may be an X₃-containing 5-membered ring or anX₃-containing 5-membered ring to which at least one 6-membered ring iscondensed, and A₄ may be an X₄-containing 5-membered ring, anX₄-containing 5-membered ring to which at least one 6-membered ring iscondensed, or an X₄-containing 6-membered ring.

In an embodiment, a group represented by

in Formula 1 may be a group represented by one of Formulae A1(1) toA1(32), which are explained below.

In an embodiment, a group represented by

in Formula 1 may be a group represented by one of Formulae A2-1 to A2-8,which are explained below.

In an embodiment, a group represented by

in Formula 1 may be a group represented by one of Formulae A3-1 toA3-15, which are explained below.

In an embodiment, a group represented by

in Formula 1 may be a group represented by one of Formulae A4-1 toA4-32, which are explained below.

In an embodiment, CY₁ may be a Y₁-containing 5-membered ring, aY₁-containing 5-membered ring condensed to at least one 6-membered ring,or a Y₁-containing 6-membered

In an embodiment, a group represented by

in Formula 1 may be a group represented by Formula CY1(a), which isexplained below.

In an embodiment, the organometallic compound is selected from Compounds1 to 105, which are explained below.

In an embodiment, the organometallic compound may emit blue light havinga maximum emission wavelength in a range of about 430 nanometers (nm) toabout 490 nm.

According to embodiments, a light-emitting device may include a firstelectrode, a second electrode facing the first electrode, an interlayerdisposed between the first electrode and the second electrode andincluding an emission layer, and an organometallic compound representedby Formula 1.

In an embodiment, the interlayer may include a first compound that isthe organometallic compound represented by Formula 1; and a secondcompound comprising at least one π electron-deficientnitrogen-containing C₁-C₆₀ cyclic group, a third compound comprising agroup represented by Formula 3, which is explained below, a fourthcompound capable of emitting delayed fluorescence, or any combinationthereof. The first compound, the second compound, the third compound,and the fourth compound may be different from one another.

In an embodiment, the emission layer may include the first compound; andthe second compound, the third compound, the fourth compound, or anycombination thereof. The emission layer may emit phosphorescence orfluorescence emitted from the first compound.

In an embodiment, the second compound may include a pyridine group, apyrimidine group, a pyrazine group, a pyridazine group, a triazinegroup, or any combination thereof.

In an embodiment, the fourth compound may be a compound including atleast one cyclic group comprising boron (B) and nitrogen (N) asring-forming atoms.

In an embodiment, the second compound may include a compound representedby Formula 2, which is explained below.

In an embodiment, at least one of Conditions 1 to 4 is satisfied, whichare explained below.

According to embodiments, an electronic apparatus may include thelight-emitting device and a thin-film transistor. The thin-filmtransistor may include a source electrode and a drain electrode, and thefirst electrode of the light-emitting device may be electricallyconnected to at least one of the source electrode and the drainelectrode of the thin-film transistor.

In an embodiment, the electronic apparatus may further include a colorfilter, a color-conversion layer, a touchscreen layer, a polarizationlayer, or any combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the disclosure will becomemore apparent by describing in detail embodiments thereof with referenceto the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view of a light-emitting deviceaccording to an embodiment;

FIG. 2 is a schematic cross-sectional view of an electronic apparatusaccording to an embodiment; and

FIG. 3 is a schematic cross-sectional view of an electronic apparatusaccording to an embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The disclosure will now be described more fully hereinafter withreference to the accompanying drawings, in which embodiments are shown.This disclosure may, however, be embodied in different forms and shouldnot be construed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the disclosure to thoseskilled in the art.

In the drawings, the sizes, thicknesses, ratios, and dimensions of theelements may be exaggerated for ease of description and for clarity.Like numbers refer to like elements throughout.

In the description, it will be understood that when an element (orregion, layer, part, etc.) is referred to as being “on”, “connected to”,or “coupled to” another element, it can be directly on, connected to, orcoupled to the other element, or one or more intervening elements may bepresent therebetween. In a similar sense, when an element (or region,layer, part, etc.) is described as “covering” another element, it candirectly cover the other element, or one or more intervening elementsmay be present therebetween.

In the description, when an element is “directly on,” “directlyconnected to,” or “directly coupled to” another element, there are nointervening elements present. For example, “directly on” may mean thattwo layers or two elements are disposed without an additional elementsuch as an adhesion element therebetween.

As used herein, the expressions used in the singular such as “a,” “an,”and “the,” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. For example, “A and/or B”may be understood to mean “A, B, or A and B.” The terms “and” and “or”may be used in the conjunctive or disjunctive sense and may beunderstood to be equivalent to “and/or”.

In the specification and the claims, the term “at least one of” isintended to include the meaning of “at least one selected from the groupof” for the purpose of its meaning and interpretation. For example, “atleast one of A and B” may be understood to mean “A, B, or A and B.” Whenpreceding a list of elements, the term, “at least one of,” modifies theentire list of elements and does not modify the individual elements ofthe list.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another element. Thus, a first element could be termed asecond element without departing from the teachings of the disclosure.Similarly, a second element could be termed a first element, withoutdeparting from the scope of the disclosure.

The spatially relative terms “below”, “beneath”, “lower”, “above”,“upper”, or the like, may be used herein for ease of description todescribe the relations between one element or component and anotherelement or component as illustrated in the drawings. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation, in addition tothe orientation depicted in the drawings. For example, in the case wherea device illustrated in the drawing is turned over, the devicepositioned “below” or “beneath” another device may be placed “above”another device. Accordingly, the illustrative term “below” may includeboth the lower and upper positions. The device may also be oriented inother directions and thus the spatially relative terms may beinterpreted differently depending on the orientations.

The terms “about” or “approximately” as used herein is inclusive of thestated value and means within an acceptable range of deviation for therecited value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the recited quantity (i.e., the limitations of themeasurement system). For example, “about” may mean within one or morestandard deviations, or within +20%, +10%, or +5% of the stated value.

It should be understood that the terms “comprises,” “comprising,”“includes,” “including,” “have,” “having,” “contains,” “containing,” andthe like are intended to specify the presence of stated features,integers, steps, operations, elements, components, or combinationsthereof in the disclosure, but do not preclude the presence or additionof one or more other features, integers, steps, operations, elements,components, or combinations thereof.

Unless otherwise defined or implied herein, all terms (includingtechnical and scientific terms) used have the same meaning as commonlyunderstood by those skilled in the art to which this disclosurepertains. It will be further understood that terms, such as thosedefined in commonly used dictionaries, should be interpreted as having ameaning that is consistent with their meaning in the context of therelevant art and should not be interpreted in an ideal or excessivelyformal sense unless clearly defined in the specification.

An organometallic compound may be represented by Formula 1:

In Formula 1, M may be platinum (Pt), palladium (Pd), nickel (Ni),copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir),ruthenium (Ru), osmium (Os), titanium (Ti), zirconium (Zr), hafnium(Hf), europium (Eu), terbium (Tb), or thulium (Tm).

In an embodiment, M in Formula 1 may be platinum (Pt), palladium (Pd),nickel (Ni), copper (Cu), silver (Ag), or gold (Au), but embodiments arenot limited thereto.

In Formula 1, X₁ to X₄ may each independently be C or N.

In an embodiment, X₁ to X₄ may each be C, or X₁ to X₃ may each be C andX₄ may be N.

In an embodiment, in Formula 1, a bond between X₁ and M may be acovalent bond, a bond between X₂ and M may be a covalent bond, a bondbetween X₃ and M may be a coordinate bond, and a bond between X₄ and Mmay be a covalent bond or a coordinate bond.

In embodiments, in Formula 1, a bond between X₁ and M may be a covalentbond, and X₁ may be C.

In embodiments, in Formula 1, a bond between X₂ and M may be a covalentbond, and X₂ may be C.

In embodiments, in Formula 1, a bond between X₃ and M may be acoordinate bond, and X₃ may be C.

In embodiments, in Formula 1, a bond between X₄ and M may be acoordinate bond, and X₄ may be C.

In embodiments, in Formula 1, a bond between X₄ and M may be a covalentbond, and X₄ may be N.

In Formula 1, Y₁ may be N.

In Formula 1, A₁ to A₄ may each independently be a C₃-C₆₀ carbocyclicgroup or a C₁-C₆₀ heterocyclic group.

In an embodiment, in Formula 1, A₁ may be an X₁-containing 6-memberedring.

In an embodiment, in Formula 1, A₂ may be an X₂-containing 6-memberedring.

In an embodiment, in Formula 1, A₃ may be an X₃-containing 5-memberedring or an X₃-containing 5-membered ring condensed with at least one6-membered ring.

In an embodiment, in Formula 1, A₄ may be an X₄-containing 5-memberedring, an X₄-containing 5-membered ring condensed with at least one6-membered ring, or an X₄-containing 6-membered ring.

In an embodiment, in Formula 1, A₃ may be an X₃-containing 5-memberedring or an X₃-containing 5-membered ring condensed with at least one6-membered ring, and A₄ may be an X₄-containing 5-membered ring, anX₄-containing 5-membered ring condensed with at least one 6-memberedring, or an X₄-containing 6-membered ring.

In an embodiment, the X₁-containing 6-membered ring in A₁, theX₂-containing 6-membered ring in A₂, and the X₄-containing 6-memberedring in A₄ may each independently be a benzene group, a pyridine group,or a pyrimidine group.

In an embodiment, the X₃-containing 5-membered ring and theX₃-containing 5-membered ring condensed with at least one 6-memberedring in A₃ and the X₄-containing 5-membered ring and the X₄-containing5-membered ring condensed with at least one 6-membered ring in A₄ mayeach independently be a pyrrole group, a pyrazole group, an imidazolegroup, a triazole group, a furan group, an oxazole group, an isooxazolegroup, a thiazole group, an isothiazole group, an oxadiazole group, or athiadiazole group.

In an embodiment, in Formula 1, a group represented by

may be a group represented by one of Formulae A1(1) to A1(32):

In Formulae A1(1) to A1(32),

X₁, T₁, and Y₁ may respectively be the same as described in connectionwith X₁, T₁, and Y₁ in Formula 1,

R₁₁ and R₁₂ may each independently be the same as described inconnection with R₁ in Formula 1,

R₅₁ and R₅₂ may each independently be the same as described inconnection with R₅ in Formula 1,

b52 may be an integer from 0 to 2,

b53 may be an integer from 0 to 3,

b54 may be an integer from 0 to 4,

Ru and R₁₂ may optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a), two R₅₁(s) of at least two R₅₁(s) when b53 is 2 orgreater may optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a), two R_(5i)(s) when b52 is 2 may optionally be boundto each other to form a C₃-C₆₀ carbocyclic group unsubstituted orsubstituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic groupunsubstituted or substituted with at least one R_(10a), two R₅₂(s) of atleast two R₅₂(s) when b54 is 2 or greater may optionally be bound toeach other to form a C₃-C₆₀ carbocyclic group unsubstituted orsubstituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic groupunsubstituted or substituted with at least one R_(10a), two R₅₂(s) of atleast two R₅₂(s) when b53 is 2 or greater may optionally be bound toeach other to form a C₃-C₆₀ carbocyclic group unsubstituted orsubstituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic groupunsubstituted or substituted with at least one R_(10a),

R_(10a) may be the same as described in connection with R_(10a) inFormula 1,

* indicates a binding site to M in Formula 1,

*′ indicates a binding site to T₄ in Formula 1, and

*″ indicates a binding site to A₂ in Formula 1.

In an embodiment, in Formula 1, a group represented by

may be a group represented by one of Formulae A1-1 to A1-4:

In Formulae A1-1 to A1-4,

X₁ may be the same as described in connection with X₁ in Formula 1,

X₁₁ and X₁₂ may each independently be the same as described inconnection with X₁ in Formula 1,

R₁ and R₁₂ may each independently be the same as described in connectionwith R₁ in Formula 1, and R₁ and R₁₂ may not each be hydrogen,

R₁ and R₁₂ may be optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a),

R_(10a) may be the same as described in connection with R_(10a) inFormula 1,

* indicates a binding site to M in Formula 1,

*′ indicates a binding site to T₄ in Formula 1,

*″ indicates a binding site to T₁ in Formula 1, and

*′″ indicates a binding site to Y₁ in Formula 1.

In an embodiment, in Formula 1, a group represented by

may be a group represented by one of Formulae A2-1 to A2-8:

In Formulae A2-1 to A2-8,

X₂ may be the same as described in connection with X₂ in Formula 1,

X₂₁ to X₂₃ may independently each be the same as described in connectionwith X₂ in Formula 1,

R₂₁ to R₂₃ may each independently be the same as described in connectionwith R₂ in Formula 1, and R₂₁ to R₂₃ may not each be hydrogen,

two of R₂₁ to R₂₃ may optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a),

R_(10a) may be the same as described in connection with R_(10a) inFormula 1,

* indicates a binding site to M in Formula 1,

*′ indicates a binding site to T₂ in Formula 1, and

*″ indicates a binding site to T₁ in Formula 1.

In an embodiment, in Formula 1, a group represented by

may be a group represented by one of Formulae A3-1 to A3-15:

In Formulae A3-1 to A3-15,

X₃ may be the same as described in connection with X₃ in Formula 1,

X₃₂ to X₃₇ may each independently be the same as described in connectionwith X₃ in Formula 1,

R₃₁ to R₃₄ may each independently be the same as described in connectionwith R₃ in Formula 1, and R₃₁ to R₃₃ may not each be hydrogen,

b34 may be an integer from 0 to 4,

two of R₃₁ to R₃₄ may optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a), two R₃₄(s) of at least two R₃₄(s) when b34 is 2 orgreater may optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a),

R_(10a) may be the same as described in connection with R_(10a) inFormula 1,

* indicates a binding site to M in Formula 1,

*″ indicates a binding site to T₂ in Formula 1, and

*′ in Formulae A3-9 to A3-12 and A3-15 may be a binding site to T₃ inFormula 1.

In an embodiment, in Formula 1, a group represented by

may be a group represented by one of Formulae A4-1 to A4-32:

In Formulae A4-1 to A4-32,

X₄ may be the same as described in connection with X₄ in Formula 1,

X₄₁ to X₄₇ may each independently be the same as described in connectionwith X₄ in Formula 1,

R₄₁ to R₄₅ may each independently be the same as described in connectionwith R₄ in Formula 1, and R₄₁ to R₄₃ may not each be hydrogen,

R₄₄ in Formulae A4-20, A4-25, A4-26, and A4-28 to A4-30 may not behydrogen,

b43 may be an integer from 0 to 3,

b44 may be an integer from 0 to 4,

two of R₄₁ to R₄₅ may optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a), two R₄₄(s) of at least two R₄₄(s) when b44 is 2 orgreater may optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a), two R₄₅(s) of at least two R₄₅(s) when b43 is 2 orgreater may optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a),

R_(10a) may be the same as described in connection with R_(10a) inFormula 1,

* indicates a binding site to M in Formula 1,

*″ indicates a binding site to T₄ in Formula 1, and

*′ in Formulae A4-9 to A4-12, A4-15, A4-31, and A4-32 may be a bindingsite to T₃ in Formula 1.

In Formula 1, CY₁ may be a C₁-C₆₀ heterocyclic group.

In an embodiment, in Formula 1, CY₁ may be a Y₁-containing 5-memberedring, a Y₁-containing 5-membered ring condensed with at least one6-membered ring, or a Y₁-containing 6-membered ring.

In an embodiment, the Y₁-containing 5-membered ring or the Y₁-containing5-membered ring condensed ring with at least one 6-membered ring in CY₁may each independently be a pyrrole group, a pyrazole group, animidazole group, a triazole group, an oxazole group, an isooxazolegroup, an isothiazole group, an oxadiazole group, or a thiadiazolegroup.

In an embodiment, the Y₁-containing 6-membered ring in CY₁ may be apyridine group or a pyrimidine group.

In embodiments, in Formula 1, a group represented by

may be a group represented by Formula CY1(a):

In Formula CY1(a),

Y_(1a) may be C or N,

CY₁₁ may be a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group,

CY₁₂ may be the same as described in connection with CY₁ in Formula 1,

R_(5a) and R_(5b) may each independently be the same as described inconnection with R₅ in Formula 1,

b5a and b5b may each independently be the same as described inconnection with b5 in Formula 1,

two R_(5a)(s) of at least two R_(5a)(s) when b5a is 2 or greater mayoptionally be bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), two R_(5b)(s) of at least two R_(5b)(s) when b5b is 2 orgreater may optionally be bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a),

R_(10a) may be the same as described in connection with R_(10a) inFormula 1,

*′ indicates a binding site to A₁ in Formula 1, and

*″ indicates a binding site to T₁ in Formula 1.

In an embodiment, in Formula 1, a group represented by

may be a group represented by Formula CY1-1 or Formula CY1-2:

In Formulae CY1-1 and CY1-2,

Y₁₂ to Y₁₈ may each independently be C or N,

R₅₁ and R₅₂ may each independently be the same as described inconnection with R₅ in Formula 1,

b52 may be an integer from 0 to 2,

b53 may be an integer from 0 to 3,

b54 may be an integer from 0 to 4,

two R₅₁(s) of at least two R₅₁(s) when b53 is 2 or greater mayoptionally be bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), two R₅₂(s) when b52 is 2 may optionally be bound to each otherto form a C₃-C₆₀ carbocyclic group unsubstituted or substituted with atleast one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted orsubstituted with at least one R_(10a), two R₅₂(s) of at least two R₅₂(s)when b54 is 2 or greater may optionally be bound to each other to form aC₃-C₆₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a),

R_(10a) may be the same as described in connection with R_(10a) inFormula 1,

*′ indicates a binding site to A₁ in Formula 1, and

*″ indicates a binding site to T₁ in Formula 1.

In Formula 1, T₁ may be N, B, P, C(Z₁₁), Si(Z₁₁), or Ge(Z₁₁).

In an embodiment, in Formula 1, T₁ may be N or C(Z₁₁), but embodimentsare not limited thereto.

In Formula 1, T₂ to T₄ may each independently be a single bond, a doublebond, *—N(Z₂₁)—*′, *—B(Z₂₁)—*′, *—P(Z₂₁)—*′, *—C(Z₂₁)(Z₂₂)—*′,*—Si(Z₂₁)(Z₂₂)—*′, *—Ge(Z₂₁)(Z₂₂)—*′, *—S—*′, *—Se—*′, *—O—*′,*—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(Z₂₁)=*′, *═C(Z₂₁)—*′,*—C(Z₂₁)═C(Z₂₂)—*′, *—C(═S)—*′, or *—C≡C—*′, and * and *′ each indicatea binding site to an adjacent atom.

In an embodiment, T₂ to T₄ may each be a single bond, but embodimentsare not limited thereto.

In Formula 1, a2 to a4 may each independently be an integer from 0 to 3.

In an embodiment, in Formula 1, a2 to a4 may each independently be 0 or1.

In an embodiment, in Formula 1, a2 and a4 may each be 1, but embodimentsare not limited thereto.

In an embodiment, in Formula 1, a3 may be 0, but embodiments are notlimited thereto.

In Formula 1, R₁ to R₅, Z₁₁, Z₁₂, Z₂₁, and Z₂₂ may each independently behydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, a C₁-C₆₀ alkyl group unsubstituted or substituted with atleast one R_(10a), a C₂-C₆₀ alkenyl group unsubstituted or substitutedwith at least one R_(10a), a C₂-C₆₀ alkynyl group unsubstituted orsubstituted with at least one R_(10a), a C₁-C₆₀ alkoxy groupunsubstituted or substituted with at least one R_(10a), a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least oneR_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), a C₆-C₆₀ aryloxy group unsubstituted orsubstituted with at least one R_(10a), a C₆-C₆₀ arylthio groupunsubstituted or substituted with at least one R_(10a), —Si(Q₁)(Q₂)(Q₃),—N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂).R_(10a) and Q₁ to Q₃ may be understood by referring to the descriptionsof R_(10a) and Q₁ to Q₃ provided herein.

In an embodiment, in Formula 1, R₁ to R₅, Z₁₁, Z₂₁, and Z₂₂ mayrespectively be understood by referring to the descriptions of R₁ to R₅,Z₁₁, Z₂₁, and Z₂₂ in paragraph [00253] to [00274] of the disclosure.

In an embodiment, R₁ to R₅, Z₁₁, Z₂₁, and Z₂₂ may each independently be:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,or a nitro group;

a C₁-C₂₀ alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, ora C₁-C₂₀ alkoxy group, each unsubstituted or substituted with deuterium,—F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxylgroup, a cyano group, a nitro group, a phenyl group, a naphthyl group,—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), or any combinationthereof;

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, or a chrysenyl group, each unsubstituted orsubstituted with deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃,—CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, a C₁-C₂₀alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group,—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), or any combinationthereof; or

—Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), or —B(Q₁)(Q₂).

In Formula 1, b1 to b5 may each independently be an integer from 0 to10.

In an embodiment, in Formula 1, b1 to b5 may each independently be aninteger from 0 to 5.

In Formula 1, two R₁(s) of at least two R₁(s) when b1 is 2 or greatermay optionally be bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), two R₂(s) of at least two R₂(s) when b2 is 2 or greater mayoptionally be bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), two R₃(s) of at least two R₃(s) when b3 is 2 or greater mayoptionally be bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), two R₄(s) of at least two R₄(s) when b4 is 2 or greater mayoptionally be bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), and two R₅(s) of at least two R₅(s) when b5 is 2 or greater mayoptionally be bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a).

In an embodiment, the organometallic compound represented by Formula 1may be selected from Compounds 1 to 105:

In embodiments, the organometallic compound represented by Formula 1 mayemit blue light. In embodiments, the organometallic compound representedby Formula 1 may emit blue light having a maximum emission wavelength ina range of about 430 nanometers (nm) to about 490 nm. For example, theorganometallic compound represented by Formula 1 may emit blue lighthaving a maximum emission wavelength in a range of about 430 nm to about485 nm. For example, the organometallic compound represented by Formula1 may emit blue light having a maximum emission wavelength in a range ofabout 440 nm to about 475 nm. For example, the organometallic compoundrepresented by Formula 1 may emit blue light having a maximum emissionwavelength in a range of about 455 nm to about 470 nm.

In the organometallic compound represented by Formula 1, Y₁ in Formula 1may be N, and thus, the organometallic compound may have a non-planarstructure. In Formula 1, a degree of intramolecular conjugation may beadjusted in the organometallic compound in which T₁ is C(Z₁₁) or N.Thus, in the light-emitting device including the organometalliccompound, formation of exciplex or excimer may be prevented between adopant and a dopant or between a dopant and a host. Accordingly, thelight-emitting device may be used in the manufacture of an electronicapparatus having a low driving voltage, excellent luminescenceefficiency, long lifespan, and excellent colorimetric purity.

Methods of synthesizing the organometallic compound represented byFormula 1 may be easily understood to those of ordinary skill in the artby referring to Synthesis Examples and Examples described herein.

According to embodiments, at least one of the organometallic compoundsrepresented by Formula 1 may be used in a light-emitting device (e.g.,an organic light-emitting device). Therefore, according to anembodiment, a light-emitting device may include a first electrode, asecond electrode facing the first electrode, an interlayer disposedbetween the first electrode and the second electrode and including anemission layer, and the organometallic compound represented by Formula1.

In an embodiment, the interlayer in the light-emitting device mayinclude a first compound as the organometallic compound represented byFormula 1; and a second compound including at least one πelectron-deficient nitrogen-containing C₁-C₆₀ cyclic group, a thirdcompound including a group represented by Formula 3, a fourth compoundthat may emit delayed fluorescence, or any combination thereof, whereinthe first compound, the second compound, the third compound, and thefourth compound may be different from one another:

In Formula 3, ring CY₇₁ and ring CY₇₂ may each independently be a Relectron-rich C₃-C₆₀ cyclic group or a pyridine group,

X₇₁ may be a single bond or a linking group including O, S, N, B, C, Si,or any combination thereof,

* in Formula 3 indicates a binding site to an adjacent atom in the thirdcompound, and

the following compounds may be excluded from the third compound:

[Descriptions of Second Compound, Third Compound, and Fourth Compound]

In an embodiment, the second compound may include a pyridine group, apyrimidine group, a pyrazine group, a pyridazine group, a triazinegroup, or any combination thereof.

In embodiments, the light-emitting device may further include at leastone of the second compound and the third compound, in addition to thefirst compound.

In embodiments, the light-emitting device may further include the fourthcompound, in addition to the first compound.

In embodiments, the light-emitting device may include the firstcompound, the second compound, the third compound, and the fourthcompound.

In embodiments, the interlayer may include the second compound. Theinterlayer may further include, in addition to the first compound andthe second compound, the third compound, the fourth compound, or anycombination thereof.

In embodiments, a difference between the triplet energy level inelectron volts (eV) of the fourth compound and the singlet energy levelin electron volts (eV) of the fourth compound may be in a range of about0 eV to about 0.5 eV. For example, the difference between the tripletenergy level in electron volts (eV) of the fourth compound and thesinglet energy level in electron volts (eV) of the fourth compound maybe in a range of about 0 eV to about 0.3 eV.

In embodiments, the fourth compound may be a compound including at leastone cyclic group including boron (B) and nitrogen (N) as ring-formingatoms.

In embodiments, the fourth compound may be a C₈-C₆₀ polycyclicgroup-containing compound including at least two condensed cyclic groupsthat share a boron atom (B).

In embodiments, the fourth compound may include a condensed ring inwhich at least one third ring may be condensed with at least one fourthring,

the third ring may be a cyclopentane group, a cyclohexane group, acycloheptane group, a cyclooctane group, a cyclopentene group, acyclohexene group, a cycloheptene group, a cyclooctene group, anadamantane group, a norbornene group, a norobornane group, abicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, abicyclo[2.2.2]octane group, a benzene group, a pyridine group, apyrimidine group, a pyridazine group, a pyrazine group, or a triazinegroup, and

the fourth ring may be a 1,2-azaborinine group, a 1,3-azaborinine group,a 1,4-azaborinine group, a 1,2-dihydro-1,2-azaborinine group, a1,4-oxaborinine group, a 1,4-thiaborinine group, or a1,4-dihydroborinine group.

In embodiments, the interlayer may include the fourth compound. Theinterlayer may include, in addition to the first compound and the fourthcompound, the second compound, the third compound, or any combinationthereof.

In embodiments, the interlayer may include the third compound. Forexample, the third compound may not include CBP described herein and acompound represented by mCBP.

In an embodiment, the emission layer in the interlayer may include: thefirst compound; and the second compound, the third compound, the fourthcompound, or any combination thereof.

In an embodiment, the emission layer may emit phosphorescence orfluorescence emitted from the first compound. In embodiments,phosphorescence or fluorescence emitted from the first compound may beblue light.

In embodiments, the emission layer in the light-emitting device mayinclude the first compound and the second compound, and the firstcompound and the second compound may form an exciplex.

In embodiments, the emission layer in the light-emitting device mayinclude the first compound, the second compound, and the third compound,and the first compound and the second compound may form an exciplex.

In embodiments, the emission layer in the light-emitting device mayinclude the first compound and the fourth compound, and the fourthcompound may improve color purity, luminescence efficiency, and lifespancharacteristics of the light-emitting device.

In embodiments, the second compound may include a compound representedby Formula 2:

In Formula 2,

L₆₁ to L₆₃ may each independently be a single bond, a C₃-C₆₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a), or aC₁-C₆₀ heterocyclic group unsubstituted or substituted with at least oneR_(10a),

b61 to b63 may each independently be an integer from 1 to 5,

X₆₄ may be N or C(R₆₄), X₆₅ may be N or C(R₆₅), X₆₆ may be N or C(R₆₆),and at least one of X₆₄ to X₆₆ may be N,

R₆₁ to R₆₆ may respectively be understood by referring to thedescriptions of R₆₁ to R₆₆ provided herein, and

R_(10a) may be understood by referring to the description of R_(10a)provided herein.

In embodiments, the third compound may include a compound represented byFormula 3-1, a compound represented by Formula 3-2, a compoundrepresented by Formula 3-3, a compound represented by Formula 3-4, acompound represented by Formula 3-5, or any combination thereof:

In Formulae 3-1 to 3-5,

ring CY₇₁ to ring CY₇₄ may each independently be a π electron-richC₃-C₆₀ cyclic group or a pyridine group,

X₈₂ may be a single bond, O, S, N-[(L₈₂)_(b82)-R₈₂],C(R_(82a))(R_(82b)), or Si(R_(82a))(R_(82b)),

X₈₃ may be a single bond, O, S, N-[(L₈₃)_(b83)-R₈₃],C(R_(83a))(R_(83b)), or Si(R_(83a))(R_(83b)),

X₈₄ may be O, S, N-[(L₈₄)_(b84)-R₈₄], C(R_(84a))(R_(84b)), orSi(R_(84a))(R_(84b)),

X₈₅ may be C or Si,

L₈₁ to L₈₅ may each independently be a single bond, *—C(Q₄)(Q₅)-*′,*—Si(Q₄)(Q₅)-*′, a π electron-rich C₃-C₆₀ cyclic group unsubstituted orsubstituted with at least one R_(10a), or a pyridine group unsubstitutedor substituted with at least one R_(10a), wherein Q₄ and Q₅ may eachindependently be the same as defined in connection with Q₁ providedherein, * and *′ each indicate a binding site to a neighboring atom,

b81 to b85 may each independently be an integer from 1 to 5,

R₇₁ to R₇₄, R₈₁ to R₈₅, R_(82a), R_(82b), R_(83a), R_(83b), R_(84a), andR_(84b) may respectively be understood by referring to the descriptionsof R₇₁ to R₇₄, R₈₁ to R₈₅, R_(82a), R_(82b), R_(83a), R_(83b), R_(84a),and R_(84b) provided herein,

a71 to a74 may each independently be an integer from 0 to 20, and

R_(10a) may be understood by referring to the description of R_(10a)provided herein.

In embodiments, the fourth compound may be a compound represented byFormula 502, a compound represented by Formula 503, or any combinationthereof:

In Formulae 502 and 503,

ring A₅₀₁ to ring A₅₀₄ may each independently be a C₃-C₆₀ carbocyclicgroup or a C₁-C₆₀ heterocyclic group,

Y₅₀₅ may be O, S, N(R₅₀₅), B(R₅₀₅), C(R_(505a))(R_(505b)), orSi(R_(505a))(R_(505b)),

Y₅₀₆ may be O, S, N(R₅₀₆), B(R₅₀₆), C(R_(506a))(R_(506b)), orSi(R_(506a))(R_(506b)),

Y₅₀₇ may be O, S, N(R₅₀₇), B(R₅₀₇), C(R_(507a))(R_(507b)), orSi(R_(507a))(R_(507b)),

Y₅₀₈ may be O, S, N(R₅₀₈), B(R₅₀₈), C(R_(508a))(R_(508b)), orSi(R_(508a))(R_(508b)),

Y₅₁ and Y₅₂ may each independently be B, P(═O), or S(═O),

R_(500a), R_(500b), R₅₀₁ to R₅₀₈, R_(505a), R_(505b), R_(506a),R_(506b), R_(507a), R_(507b), R_(508a), and R_(508b) may respectively beunderstood by referring to the descriptions of R_(500a), R_(500b), R₅₀₁to R₅₀₈, R_(505a), R_(505b), R_(506a), R_(506b), R_(507a), R_(507b),R_(508a), and R_(508b) provided herein,

a501 to a504 may each independently be an integer from 0 to 20, and

R_(10a) may be understood by referring to the description of R_(10a)provided herein.

[Description of Formulae 2, 3, 3-1 to 3-5, 502, and 503]

In Formula 2, b61 to b63 may respectively indicate the number of L₆₁(s)to L₆₃(s), and b61 to b63 may each independently be an integer from 1 to5. When b61 is 2 or greater, at least two L₆₁(s) may be identical to ordifferent from each other, when b62 is 2 or greater, at least two L₆₂(s)may be identical to or different from each other, and when b63 is 2 orgreater, at least two L₆₃(s) may be identical to or different from eachother. In embodiments, b61 to b63 may each independently be 1 or 2.

In an embodiment, in Formula 2, L₆₁ to L₆₃ may each independently be:

a single bond; or

a benzene group, a naphthalene group, an anthracene group, aphenanthrene group, a triphenylene group, a pyrene group, a chrysenegroup, a cyclopentadiene group, a furan group, a thiophene group, asilole group, an indene group, a fluorene group, an indole group, acarbazole group, a benzofuran group, a dibenzofuran group, abenzothiophene group, a dibenzothiophene group, a benzosilole group, adibenzosilole group, an azafluorene group, an azacarbazole group, anazadibenzofuran group, an azadibenzothiophene group, an azadibenzosilolegroup, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a triazine group, a quinoline group, an isoquinolinegroup, a quinoxaline group, a quinazoline group, a phenanthroline group,a pyrrole group, a pyrazole group, an imidazole group, a triazole group,an oxazole group, an isooxazole group, a thiazole group, an isothiazolegroup, an oxadiazole group, a thiadiazole group, a benzopyrazole group,a benzimidazole group, a benzoxazole group, a benzothiazole group, abenzoxadiazole group, a benzothiadiazole group, a dibenzooxasilinegroup, a dibenzothiasiline group, a dibenzodihydroazasiline group, adibenzodihydrodisiline group, a dibenzodihydrosiline group, adibenzodioxane group, a dibenzooxathiene group, a dibenzooxazine group,a dibenzopyran group, a dibenzodithiine group, a dibenzothiazine group,a dibenzothiopyran group, a dibenzocyclohexadiene group, adibenzodihydropyridine group, or a dibenzodihydropyrazine group, eachunsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, a pyridinylgroup, a pyrimidinyl group, a triazinyl group, a fluorenyl group, adimethylfluorenyl group, a diphenylfluorenyl group, a carbazolyl group,a phenylcarbazolyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a dibenzosilolyl group, a dimethyldibenzosilolyl group, adiphenyldibenzosilolyl group, —O(Q₃₁), —S(Q₃₁), —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —P(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁),—P(═O)(Q₃₁)(Q₃₂), or any combination thereof,

wherein Q₃₁ to Q₃₃ may each independently be hydrogen, deuterium, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenylgroup, a terphenyl group, a pyridinyl group, a pyrimidinyl group, apyridazinyl group, a pyrazinyl group, or a triazinyl group.

In embodiments, in Formula 2, a bond between L₆₁ and R₆₁, a bond betweenL₆₂ and R₆₂, a bond between L₆₃ and R₆₃, a bond between at least twoL₆₁(s), a bond between at least two L₆₂(s), a bond between at least twoL₆₃(s), a bond between L₆₁ and a carbon atom between X₆₄ and X₆₅ inFormula 2, a bond between L₆₂ and a carbon atom between X₆₄ and X₆₆ inFormula 2, and a bond between L₆₃ and a carbon atom between X₆₅ and X₆₆in Formula 2 may each be a carbon-carbon single bond.

In Formula 2, X₆₄ may be N or C(R₆₄), X₆₅ may be N or C(R₆₅), X₆₆ may beN or C(R₆₆), and at least one of X₆₄ to X₆₆ may be N. R₆₄ to R₆₆ mayrespectively be understood by referring to the descriptions of R₆₄ toR₆₆ provided herein. In embodiments, two or three of X₆₄ to X₆₆ may eachbe N.

R₆₁ to R₆₆, R₇₁ to R₇₄, R₈₁ to R₈₅, R_(82a), R_(82b), R_(83a), R_(83b),R_(84a) and R_(84b), R_(500a), R_(500b), R₅₀₁ to R₅₀₈, R_(505a),R_(505b), R_(506a), R_(506b), R_(507a), R_(507b), R_(508a), and R_(508b)may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl groupunsubstituted or substituted with at least one R_(10a), a C₂-C₆₀ alkenylgroup unsubstituted or substituted with at least one R_(10a), a C₂-C₆₀alkynyl group unsubstituted or substituted with at least one R_(10a), aC₁-C₆₀ alkoxy group unsubstituted or substituted with at least oneR_(10a), a C₃-C₆₀ carbocyclic group unsubstituted or substituted with atleast one R_(10a), a C₁-C₆₀ heterocyclic group unsubstituted orsubstituted with at least one R_(10a), a C₆-C₆₀ aryloxy groupunsubstituted or substituted with at least one R_(10a), a C₆-C₆₀arylthio group unsubstituted or substituted with at least one R_(10a),—C(Q₁)(Q₂)(Q₃), —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁),—S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂). Q₁ to Q₃ may respectively be understoodby referring to the descriptions of Q₁ to Q₃ provided herein.

For example, i) R₁ to R₅, Z₁₁, Z₂₁, and Z₂₂ in Formula 1, ii) R₁₁, R₁₂,R₂₁, R₂₂, R₃₁ to R₃₄, R₄₁ to R₄₅, R_(5a), R_(5b), R₅₁, and R₅₂ inFormulae A1(1) to A1(32), A1-1 to A1-4, A2-1 to A2-8, A3-1 to A3-15,A4-1 to A4-32, CY1(a), CY1-1, and CY1-2, iii) R₅₁ to R₅₆, R₇₁ to R₇₄,R₈₁ to R₈₅, R_(82a), R_(82b), R_(83a), R_(83b), R_(84a) and R_(84b),R_(500a), R_(500b), R₅₀₁ to R₅₀₈, R_(505a), R_(505b), R_(506a),R_(506b), R_(507a), R_(507b), R_(508a), and R_(508b) in Formulae 2, 3-1to 3-5, 502, and 503, and iv) R_(10a) may each independently be:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, a C₁-C₂₀ alkyl group, or a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted withdeuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, ahydroxyl group, a cyano group, a nitro group, a C₁-C₁₀ alkyl group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctylgroup, an adamantanyl group, a norbornanyl group, a norbornenyl group, acyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, aphenyl group, a biphenyl group, a naphthyl group, a pyridinyl group, apyrimidinyl group, or any combination thereof,

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclooctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a biphenyl group, a C₁-C₁₀alkylphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, abenzoisothiazolyl group, a benzoxazolyl group, a benzoisoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, an imidazopyrimidinyl group, an azacarbazolyl group, anazadibenzofuranyl group, an azadibenzothiophenyl group, an azafluorenylgroup, an azadibenzosilolyl group, or a group represented by Formula 91,each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I,—CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group,a nitro group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctylgroup, an adamantanyl group, a norbornanyl group, a norbornenyl group, acyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, aphenyl group, a biphenyl group, a C₁-C₁₀ alkylphenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, abenzofuranyl group, a benzothiophenyl group, a benzoisothiazolylgroup, abenzoxazolyl group, a benzoisoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, animidazopyrimidinyl group, —O(Q₃₁), —S(Q₃₁), —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —P(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁),—P(═O)(Q₃₁)(Q₃₂), or any combination thereof; or

—C(Q₁)(Q₂)(Q₃), —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁),—S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂),

wherein Q₁ to Q₃ and Q₃₁ to Q₃₃ may each independently be selected from:

—CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃,—CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, or —CD₂CDH₂; or

an n-propyl group, an iso-propyl group, an n-butyl group, an isobutylgroup, a sec-butyl group, a tert-butyl group, an n-pentyl group, anisopentyl group, a sec-pentyl group, a tert-pentyl group, a phenylgroup, a naphthyl group, a pyridinyl group, a pyrimidinyl group, apyridazinyl group, a pyrazinyl group, or a triazinyl group, eachunsubstituted or substituted with deuterium, a C₁-C₁₀ alkyl group, aphenyl group, a biphenyl group, a pyridinyl group, a pyrimidinyl group,a pyridazinyl group, a pyrazinyl group, a triazinyl group, or anycombination thereof:

wherein in Formula 91,

ring CY₉₁ and ring CY₉₂ may each independently be a C₅-C₃₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀heterocyclic group unsubstituted or substituted with at least oneR_(10a),

X₉₁ may be a single bond, O, S, N(R₉₁), B(R₉₁), C(R_(91a))(R_(91b)), orSi(R_(91a))(R_(91b)),

R₉₁, R_(91a), and R_(91b) may respectively be the same as defined inconnection with R₈₂, R_(82a), and R_(82b) provided herein,

R_(10a) may be understood by referring to the description of R_(10a)provided herein, and

* indicates a binding site to an adjacent atom.

In embodiments, in Formula 91,

ring CY₉₁ and ring CY₉₂ may each independently be a benzene group, apyridine group, a pyrimidine group, a pyrazine group, a pyridazinegroup, or a triazine group, each unsubstituted or substituted with atleast one R_(10a),

R₉₁, R_(91a) and R_(91b) may each independently be:

hydrogen or a C₁-C₁₀ alkyl group; or

a phenyl group, a pyridinyl group, a pyrimidinyl group, a pyridazinylgroup, a pyrazinyl group, or a triazinyl group, each unsubstituted orsubstituted with deuterium, a C₁-C₁₀ alkyl group, a phenyl group, abiphenyl group, a pyridinyl group, a pyrimidinyl group, a pyridazinylgroup, a pyrazinyl group, a triazinyl group, or any combination thereof.

In embodiments, i) R₁ to R₅, Z₁₁, Z₂₁, and Z₂₂ in Formula 1, ii) R₁₁,R₁₂, R₂₁, R₂₂, R₃₁ to R₃₄, R₄₁ to R₄₅, R_(5a), R_(5b), R₅₁, and R₅₂ inFormulae A1(1) to A1(32), A1-1 to A1-4, A2-1 to A2-8, A3-1 to A3-15,A4-1 to A4-32, CY1(a), CY1-1, and CY1-2, iii) R₅₁ to R₅₆, R₇₁ to R₇₄,R₈₁ to R₈₅, R_(82a), R_(82b), R_(83a), R_(83b), R_(84a) and R_(84b),R_(500a), R_(500b), R₅₀₁ to R₅₀₈, R_(505a), R_(505b), R_(506a),R_(506b), R_(507a), R_(507b), R_(508a), and R_(508b) in Formulae 2, 3-1to 3-5, 502, and 503, and iv) R_(10a) may each independently be:

hydrogen, deuterium, —F, a cyano group, a nitro group, —CH₃, —CD₃,—CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a group represented by one of Formulae9-1 to 9-19, a group represented by one of Formulae 10-1 to 10-246,—C(Q₁)(Q₂)(Q₃), —Si(Q₁)(Q₂)(Q₃), or —P(═O)(Q₁)(Q₂), wherein Q₁ to Q₃ mayrespectively be understood by referring to the descriptions of Q₁ to Q₃provided herein:

wherein, in Formulae 9-1 to 9-19 and 10-1 to 10-246, * indicates abinding site to an adjacent atom, “Ph” represents a phenyl group, and“TMS” represents a trimethylsilyl group.

In Formulae 3-1 to 3-5, 502, and 503, a71 to a74 and a501 to a504 mayrespectively indicate the number of R₇₁(s) to R₇₄(s) and R₅₀₁(s) toR₅₀₄(s), and a71 to a74 and a501 to a504 may each independently be aninteger from 0 to 20. When a71 is 2 or greater, at least two R₇₁(s) maybe identical to or different from each other, when a72 is 2 or greater,at least two R₇₂(s) may be identical to or different from each other,when a73 is 2 or greater, at least two R₇₃(s) may be identical to ordifferent from each other, when a74 is 2 or greater, at least two R₇₄(s)may be identical to or different from each other, when a501 is 2 orgreater, at least two R₅₀₁(s) may be identical to or different from eachother, when a502 is 2 or greater, at least two R₅₀₂(s) may be identicalto or different from each other, when a503 is 2 or greater, at least twoR₅₀₃(s) may be identical to or different from each other, and when a504is 2 or greater, at least two R₅₀₄(s) may be identical to or differentfrom each other. In embodiments, a71 to a74 and a501 to a504 may eachindependently be an integer from 0 to 8.

In embodiments, in Formula 2, the group represented by *-(L₆₁)_(b61)-R₆₁and the group represented by *-(L₆₂)_(b62)-R₆₂ may not be a phenylgroup.

In embodiments, in Formula 2, the group represented by *-(L₆₁)_(b61)-R₆₁may be identical to the group represented by *-(L₆₂)_(b62)-R₆₂.

In embodiments, in Formula 2, the group represented by *-(L₆₁)_(b61)-R₆₁and the group represented by *-(L₆₂)_(b62)-R₆₂ may be different fromeach other.

In embodiments, in Formula 2, b61 and b62 may each independently be 1,2, or 3, L₆₁ and L₆₂ may each independently be a benzene group, apyridine group, a pyrimidine group, a pyridazine group, a pyrazinegroup, or a triazine group, each unsubstituted or substituted with atleast one R_(10a).

In embodiments, in Formula 2, R₆₁ and R₆₂ may each independently be aC₃-C₆₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), a C₆-C₆₀ aryloxy group unsubstituted orsubstituted with at least one R_(10a), a C₆-C₆₀ arylthio groupunsubstituted or substituted with at least one R_(10a), —C(Q₁)(Q₂)(Q₃),or —Si(Q₁)(Q₂)(Q₃),

wherein Q₁ to Q₃ may each independently be a C₃-C₆₀ carbocyclic group ora C₁-C₆₀ heterocyclic group, each unsubstituted or substituted withdeuterium, —F, a cyano group, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxygroup, a phenyl group, a biphenyl group, or any combination thereof.

In embodiments,

in Formula 2, the group represented by *-(L₆₁)_(b61)-R₁ may be a grouprepresented by one of Formulae CY51-1 to CY51-26,

in Formula 2, the group represented by *-(L₆₂)_(b62)-R₆₂ may be a grouprepresented by one of Formulae CY52-1 to CY52-26, and/or

in Formula 2, the group represented by *-(L₆₃)_(b63)-R₆₃ may be a grouprepresented by one of Formulae CY53-1 to CY53-27, —C(Q₁)(Q₂)(Q₃), or—Si(Q₁)(Q₂)(Q₃):

wherein in Formulae CY51-1 to CY51-26, CY52-1 to CY52-26, and CY53-1 toCY53-27,

Y₆₃ may be a single bond, O, S, N(R₆₃), B(R₆₃), C(R_(63a))(_(63b)), orSi(R_(63a))(R_(63b)),

Y₆₄ may be a single bond, O, S, N(R₆₄), B(R₆₄), C(R_(64a))(R_(64b)), orSi(R_(64a))(R_(64b)),

Y₆₇ may be a single bond, O, S, N(R₆₇), B(R₆₇), C(R_(67a))(R_(67b)), orSi(R_(67a))(R_(67b)),

Y₆₈ may be a single bond, O, S, N(R₆₈), B(R_(6s)), C(R_(68a))(R_(68b)),or Si(R_(68a))(R_(68b)),

Y₆₃ and Y₆₄ in Formulae CY51-16 and CY51-17 may not be a single bond atthe same time,

Y₆₇ and Y₆₈ in Formulae CY52-16 and CY52-17 may not be a single bond atthe same time,

R_(51a) to R_(51e), R₆₁ to R₆₄, R_(63a), R_(63b), R_(64a), and R_(64b)may each independently be the same as defined in connection with R₅₁,and R_(51a) to R_(51e) may not each be hydrogen,

R_(52a) to R_(52e), R₆₅ to R₆₈, R_(67a), R_(67b), R_(68a), and R_(68b)may each independently be the same as defined in connection with R₅₂,and R_(52a) to R_(52e) may not each be hydrogen,

R_(53a) to R_(53e), R_(69a), and R_(69b) may each independently be thesame as defined in connection with R₅₃, and R_(53a) to R_(53e) may noteach be hydrogen, and

* indicates a binding site to an adjacent atom.

In embodiments,

R_(51a) to R_(51e) and R_(52a) to R_(52e) in Formulae CY51-1 to CY51-26and Formulae CY52-1 to 52-26 may each independently be:

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclooctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a biphenyl group, a C₁-C₁₀alkylphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, abenzoisothiazolyl group, a benzoxazolyl group, a benzoisoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, an imidazopyrimidinyl group, an azacarbazolyl group, anazadibenzofuranyl group, an azadibenzothiophenyl group, an azafluorenylgroup, an azadibenzosilolyl group, or a group represented by Formula 91,each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I,—CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group,a nitro group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctylgroup, an adamantanyl group, a norbornanyl group, a norbornenyl group, acyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, aphenyl group, a biphenyl group, a C₁-C₁₀ alkylphenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, abenzofuranyl group, a benzothiophenyl group, a benzoisothiazolyl group,a benzoxazolyl group, a benzoisoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, animidazopyrimidinyl group, or any combination thereof, or

—C(Q₁)(Q₂)(Q₃) or —Si(Q₁)(Q₂)(Q₃),

wherein Q₁ to Q₃ may each independently be a phenyl group, a naphthylgroup, a pyridinyl group, a pyrimidinyl group, a pyridazinyl group, apyrazinyl group, or a triazinyl group, each unsubstituted or substitutedwith deuterium, a C₁-C₁₀ alkyl group, a phenyl group, a biphenyl group,a pyridinyl group, a pyrimidinyl group, a pyridazinyl group, a pyrazinylgroup, a triazinyl group, or any combination thereof,

in Formulae CY51-16 and CY51-17, i) Y₆₃ may be O or S, and Y₆₄ may beSi(R_(64a))(R_(64b)), or ii) Y₆₃ may be Si(R_(63a))(R_(63b)), and Y₆₄may be O or S, and

in Formulae CY52-16 and CY52-17, i) Y₆₇ may be O or S, and Y₆₈ may beSi(R_(68a))(R_(68b)), or ii) Y₆₇ may be Si(R_(67a))(R_(67b)), and Y₆₈may be O or S.

In Formulae 3-1 to 3-5, L₈₁ to L₈₅ may each independently be:

a single bond; or

*—C(Q₄)(Q₅)-*′ or *—Si(Q₄)(Q₅)-*′; or

a benzene group, a naphthalene group, an anthracene group, aphenanthrene group, a triphenylene group, a pyrene group, a chrysenegroup, a cyclopentadiene group, a furan group, a thiophene group, asilole group, an indene group, a fluorene group, an indole group, acarbazole group, a benzofuran group, a dibenzofuran group, abenzothiophene group, a dibenzothiophene group, a benzosilole group, adibenzosilole group, an azafluorene group, an azacarbazole group, anazadibenzofuran group, an azadibenzothiophene group, an azadibenzosilolegroup, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a triazine group, a quinoline group, an isoquinolinegroup, a quinoxaline group, a quinazoline group, a phenanthroline group,a pyrrole group, a pyrazole group, an imidazole group, a triazole group,an oxazole group, an isooxazole group, a thiazole group, an isothiazolegroup, an oxadiazole group, a thiadiazole group, a benzopyrazole group,a benzimidazole group, a benzoxazole group, a benzothiazole group, abenzoxadiazole group, or a benzothiadiazole group, each unsubstituted orsubstituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group,a triazinyl group, a fluorenyl group, a dimethylfluorenyl group, adiphenylfluorenyl group, a carbazolyl group, a phenylcarbazolyl group, adibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group,a dimethyldibenzosilolyl group, a diphenyldibenzosilolyl group, —O(Q₃₁),—S(Q₃₁), —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —P(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), —P(═O)(Q₃₁)(Q₃₂), or any combination thereof,

wherein Q₄, Q₅, and Q₃₁ to Q₃₃ may each independently be hydrogen,deuterium, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group,a biphenyl group, a terphenyl group, a pyridinyl group, a pyrimidinylgroup, a pyridazinyl group, a pyrazinyl group, or a triazinyl group.

In embodiments, in Formulae 3-1 and 3-2, a group represented by

may be represented by one of Formulae CY71-1(1) to CY71-1(8),

in Formulae 3-1 and 3-3, a group represented by

may be represented by one of Formulae CY71-2(1) to CY71-2(8),

in Formulae 3-2 and 3-4, a group represented by

may be represented by one of Formulae CY71-3(1) to CY71-3(32),

in Formulae 3-3 to 3-5, a group represented by

may be represented by one of Formulae CY71-4(1) to CY71-4(32), and/or

in Formula 3-5, a group represented by

may be represented by one of Formulae CY71-5(1) to CY71-5(8):

wherein in Formulae CY71-1(1) to CY71-1(8), CY71-2(1) to CY71-2(8),CY71-3(1) to CY71-3(32), CY71-4(1) to CY71-4(32), and CY71-5(1) toCY71-5(8),

X₈₁ to X₈₅, L₈₁, b81, R₈₁, and R₈₅ may respectively be understood byreferring to the descriptions of X₈₁ to X₈₅, L₈₁, b81, R₈₁, and R₈₅provided herein,

X₈₆ may be a single bond, O, S, N(R₈₆), B(R₈₆), C(R_(86a))(R_(86b)), orSi(R_(86a))(R_(86b)),

X₈₇ may be a single bond, O, S, N(R₈₇), B(R₈₇), C(R_(87a))(R_(87b)), orSi(R_(87a))(R_(87b)),

in Formulae CY71-1(1) to CY71-1(8) and CY71-4(1) to CY71-4(32), X₈₆ andX₈₇ may not be a single bond at the same time,

X₈₈ may be a single bond, O, S, N(R₈₈), B(R₈₈), C(R_(88a))(R_(88b)), orSi(R_(88a))(R_(88b)),

X₈₉ may be a single bond, O, S, N(R₈₉), B(R₈₉), C(R_(89a))(R_(89b)), orSi(R_(89a))(R_(89b)),

in Formulae CY71-2(1) to CY71-2(8), CY71-3(1) to CY71-3(32), andCY71-5(1) to CY71-5(8), X₈₈ and X₈₉ may not be a single bond at the sametime, and

R₈₆ to R₈₉, R_(86a), R_(86b), R_(87a), R_(87b), R_(88a), R_(88b),R_(89a), and R_(89b) may each independently be the same as defined inconnection with R₈₁ provided herein.

[Examples of Second Compound, Third Compound, and Fourth Compound]

In embodiments, the second compound may include at least one ofCompounds ETH1 to ETH84:

In embodiments, the third compound may include at least one of CompoundsHTH1 to HTH52:

In embodiments, the fourth compound may include at least one ofCompounds DFD1 to DFD12:

In Compounds ETH1 to ETH84, HTH1 to HTH52, and DFD1 to DFD12, “Ph”represents a phenyl group, “D₅” represents substitution with fivedeuterium atoms, and “D₄” represents substitution with four deuteriumatoms. For example, a group represented by

may be identical to a group represented by

In embodiments, the light-emitting device may satisfy at least one ofConditions 1 to 4:

[Condition 1]

LUMO energy level in electron volts (eV) of the third compound >LUMOenergy level in electron volts (eV) of the first compound

[Condition 2]

LUMO energy level in electron volts (eV) of the first compound >LUMOenergy level in electron volts (eV) of the second compound

[Condition 3]

HOMO energy level in electron volts (eV) of the first compound >HOMOenergy level in electron volts (eV) of the third compound

[Condition 4]

HOMO energy level in electron volts (eV) of the third compound >HOMOenergy level in electron volts (eV) of the second compound

The HOMO and LUMO energy levels of the first compound, the secondcompound, and the third compound may each be a negative value. The HOMOand LUMO energy levels may each be an actual measurement value, or theHOMO and LUMO energy levels may each be a value evaluated according to adensity functional theory (DFT) method.

In embodiments, an absolute value of a difference between the LUMOenergy level of the first compound and the LUMO energy level of thesecond compound may be in a range of about 0.1 eV to about 1.0 eV, anabsolute value of a difference between the LUMO energy level of thefirst compound and the LUMO energy level of the third compound may be ina range of about 0.1 eV to about 1.0 eV, an absolute value of adifference between the HOMO energy level of the first compound and theHOMO energy level of the second compound may be equal to or less thanabout 1.25 eV (e.g., about 1.25 eV or lower and about 0.2 eV or higher),and an absolute value of a difference between the HOMO energy level ofthe first compound and the HOMO energy level of the third compound maybe equal to or less than about 1.25 eV (e.g., about 1.25 eV or lower andabout 0.2 eV or higher).

When the relationships between LUMO energy level and HOMO energy levelsatisfy the conditions as described above, a balance between holes andelectrons injected into the emission layer may exist.

The light-emitting device may have a structure of a first embodiment ora second embodiment:

[Description of First Embodiment]

According to a first embodiment, the first compound may be included inan emission layer in an interlayer of a light-emitting device, whereinthe emission layer may further include a host, the first compound may bedifferent from the host, and the emission layer may emit phosphorescenceor fluorescence from the first compound. For example, according to thefirst embodiment, the first compound may be a dopant or an emitter. Inembodiments, the first compound may be a phosphorescent dopant or aphosphorescence emitter.

Phosphorescence or fluorescence emitted from the first compound may beblue light.

The emission layer may further include an ancillary dopant. Theancillary dopant may serve to improve luminescence efficiency from thefirst compound by effectively transferring energy to the first compoundas a dopant or an emitter.

The ancillary dopant may be different from the first compound and thehost.

In embodiments, the ancillary dopant may be a delayedfluorescence-emitting compound.

In embodiments, the ancillary dopant may be a compound including atleast one cyclic group including boron (B) and nitrogen (N) asring-forming atoms.

[Description of Second Embodiment]

According to a second embodiment, the first compound may be included inan emission layer in an interlayer of a light-emitting device, whereinthe emission layer may further include a host and a dopant, the firstcompound may be different from the host and the dopant, and the emissionlayer may emit phosphorescence or fluorescence (e.g., delayedfluorescence) from the dopant.

For example, the first compound in the second embodiment may serve as anancillary dopant that transfers energy to a dopant (or an emitter), andmay not serve as a dopant.

In embodiments, the first compound in the second embodiment may serve asan emitter and as an ancillary dopant that transfers energy to a dopant(or an emitter).

For example, phosphorescence or fluorescence emitted from the dopant (orthe emitter) in the second embodiment may be blue phosphorescence orblue fluorescence (e.g., blue delayed fluorescence).

The dopant (or the emitter) in the second embodiment may be aphosphorescent dopant material (e.g., the organometallic compoundrepresented by Formula 1, the organometallic compound represented byFormula 401, or any combination thereof) or any fluorescent dopantmaterial (e.g., the compound represented by Formula 501, the compoundrepresented by Formula 502, the compound represented by Formula 503, orany combination thereof).

In the first embodiment and the second embodiment, the blue light may beblue light having a maximum emission wavelength in a range of about 430nanometers (nm) to about 490 nm. For example, the blue light may have amaximum emission wavelength in a range of about 430 nm to about 485 nm.For example, the blue light may have a maximum emission wavelength in arange of about 440 nm to about 475 nm. For example, the blue light mayhave a maximum emission wavelength in a range of about 455 nm to about470 nm.

The ancillary dopant in the first embodiment may include, e.g. thefourth compound represented by Formula 502 or Formula 503.

The host in the first embodiment and the second embodiment may be anyhost material (e.g., the compound represented by Formula 301, thecompound represented by 301-1, the compound represented by Formula301-2, or any combination thereof).

In embodiments, the host in the first embodiment and the secondembodiment may be the second compound, the third compound, or anycombination thereof.

In embodiments, the light-emitting device may further include at leastone of a first capping layer located outside a first electrode and asecond capping layer located outside a second electrode, and at leastone of the first capping layer and the second capping layer may includethe organometallic compound represented by Formula 1. The first cappinglayer and the second capping layer may respectively be understood byreferring to the descriptions of the first capping layer and the secondcapping layer provided herein.

In embodiments, the light-emitting device may include: a first cappinglayer located outside the first electrode and including theorganometallic compound represented by Formula 1; a second capping layerlocated outside the second electrode and including the organometalliccompound represented by Formula 1; or the first capping layer and thesecond capping layer.

The expression that an “(interlayer and/or a capping layer) includes atleast one organometallic compound represented by Formula 1” as usedherein may be construed as meaning that the “(interlayer and/or thecapping layer) may include one organometallic compound of Formula 1 ortwo different organometallic compounds of Formula 1”.

For example, the interlayer and/or the capping layer may includeCompound D1 only as the organometallic compound. In this embodiment,Compound D1 may be included in the emission layer of the light-emittingdevice. In embodiments, Compounds D1 and D2 may be included in theinterlayer as organometallic compounds. In this embodiment, Compounds D1and D2 may be included in the same layer (for example, both Compounds D1and D2 may be included in an emission layer) or in different layers (forexample, Compound D1 may be included in an emission layer, and CompoundD2 may be included in an electron transport region).

The term “interlayer” as used herein refers to a single layer ormultiple layers located between a first electrode and a second electrodein a light-emitting device.

According to embodiments, an electronic apparatus may include thelight-emitting device. The electronic apparatus may further include athin-film transistor. In embodiments, the electronic apparatus mayfurther include a thin-film transistor including a source electrode anddrain electrode, and a first electrode of the light-emitting device maybe electrically connected to the source electrode or the drainelectrode. In an embodiment, the electronic apparatus may furtherinclude a color filter, a color-conversion layer, a touchscreen layer, apolarization layer, or any combination thereof. The electronic apparatusmay be understood by referring to the description of the electronicapparatus provided herein.

[Description of FIG. 1]

FIG. 1 is a schematic cross-sectional view of a light-emitting device 10according to an embodiment. The light-emitting device 10 may include afirst electrode 110, an interlayer 130, and a second electrode 150.

Hereinafter, the structure of the light-emitting device 10 according toan embodiment and a method of manufacturing the light-emitting device 10according to an embodiment will be described in connection with FIG. 1.

[First Electrode 110]

In FIG. 1, a substrate may be further included under the first electrode110 or above the second electrode 150. The substrate may be a glasssubstrate or a plastic substrate. The substrate may be a flexiblesubstrate including plastic having excellent heat resistance anddurability, for example, polyimide, polyethylene terephthalate (PET),polycarbonate, polyethylene naphthalate, polyarylate (PAR),polyetherimide, or any combination thereof.

The first electrode 110 may be formed by depositing or sputtering, onthe substrate, a material for forming the first electrode 110. When thefirst electrode 110 is an anode, a high work function material that mayeasily inject holes may be used as a material for a first electrode 110.

The first electrode 110 may be a reflective electrode, a transflectiveelectrode, or a transmissive electrode. When the first electrode 110 isa transmissive electrode, a material for forming the first electrode 110may be indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide(SnO₂), zinc oxide (ZnO), or any combinations thereof. In embodiments,when the first electrode 110 is a transflective electrode or areflective electrode, magnesium (Mg), silver (Ag), aluminum (Al),aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In),magnesium-silver (Mg—Ag), or any combination thereof may be used as amaterial for forming the first electrode 110.

The first electrode 110 may have a structure consisting of a singlelayer or a structure including two or more layers. In embodiments, thefirst electrode 110 may have a triple-layered structure of ITO/Ag/ITO.

[Interlayer 130]

The interlayer 130 may be on the first electrode 110. The interlayer 130may include an emission layer.

The interlayer 130 may further include a hole transport region betweenthe first electrode 110 and the emission layer and an electron transportregion between the emission layer and the second electrode 150.

The interlayer 130 may further include metal-containing compounds suchas organometallic compounds, inorganic materials such as quantum dots,and the like, in addition to various organic materials.

The interlayer 130 may include at least two emitting units sequentiallystacked between the first electrode 110 and the second electrode 150;and a charge generation layer between the at least two emitting units.When the interlayer 130 includes the at least two emitting units and acharge generation layer, the light-emitting device 10 may be a tandemlight-emitting device.

[Hole transport region in interlayer 130]

The hole transport region may have a structure consisting of a layerconsisting of a single material, a structure consisting of a layerincluding different materials, or a multi-layered structure havinglayers including a plurality of different materials.

The hole transport region may include a hole injection layer, a holetransport layer, an emission auxiliary layer, an electron blockinglayer, or a combination thereof.

For example, the hole transport region may have a multi-layeredstructure, e.g., a hole injection layer/hole transport layer structure,a hole injection layer/hole transport layer/emission auxiliary layerstructure, a hole injection layer/emission auxiliary layer structure, ahole transport layer/emission auxiliary layer structure, or a holeinjection layer/hole transport layer/electron blocking layer structure,wherein layers of each structure may be stacked on the first electrode110 in its respective stated order, but embodiments are not limitedthereto.

The hole transport region may include the compound represented byFormula 201, the compound represented by Formula 202, or any combinationthereof:

In Formulae 201 and 202,

L₂₀₁ to L₂₀₄ may each independently be a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a),

L₂₀₅ may be *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a C₁-C₂₀ alkylene groupunsubstituted or substituted with at least one R_(10a), a C₂-C₂₀alkenylene group unsubstituted or substituted with at least one R_(10a),a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at leastone R_(10a), or a C₁-C₆₀ heterocyclic group unsubstituted or substitutedwith at least one R_(10a), and * and each indicate a binding site to aneighboring atom,

xa1 to xa4 may each independently be an integer from 0 to 5,

xa5 may be an integer from 1 to 10,

R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be a C₃-C₆₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a),

R₂₀₁ and R₂₀₂ may optionally be bound to each other via a single bond, aC₁-C₅ alkylene group unsubstituted or substituted with at least oneR_(10a), or a C₂-C₅ alkenylene group unsubstituted or substituted withat least one R_(10a) to form a C₈-C₆₀ polycyclic group (e.g., acarbazole group or the like) unsubstituted or substituted with at leastone R_(10a) (e.g., Compound HT16 described herein),

R₂₀₃ and R₂₀₄ may optionally be bound to each other via a single bond, aC₁-C₅ alkylene group unsubstituted or substituted with at least oneR_(10a), or a C₂-C₅ alkenylene group unsubstituted or substituted withat least one R_(10a) to form a C₈-C₆₀ polycyclic group unsubstituted orsubstituted with at least one R_(10a), and R_(10a) may be understood byreferring to the description of R_(10a) provided herein, and

na1 may be an integer from 1 to 4.

In embodiments, Formulae 201 and 202 may each include at least one ofgroups represented by Formulae CY201 to CY217:

In Formulae CY201 to CY217, R_(10b) and R_(10c) may each independentlybe the same as described in connection with R_(10a), ring CY₂₀₁ to ringCY₂₀₄ may each independently be a C₃-C₂₀ carbocyclic group or a C₁-C₂₀heterocyclic group, and at least one hydrogen in Formulae CY201 to CY217may be unsubstituted or substituted with R_(10a).

In embodiments, in Formulae CY201 to CY217, ring CY₂₀₁ to ring CY₂₀₄ mayeach independently be a benzene group, a naphthalene group, aphenanthrene group, or an anthracene group.

In embodiments, Formulae 201 and 202 may each include at least one ofgroups represented by Formulae CY201 to CY203.

In embodiments, Formula 201 may include at least one of groupsrepresented by Formulae CY201 to CY203 and at least one of groupsrepresented by Formulae CY204 to CY217.

In embodiments, in Formula 201, xa1 may be 1, R₂₀₁ may be a grouprepresented by any one of Formulae CY201 to CY203, xa2 may be 0, andR₂₀₂ may be a group represented by any one of Formulae CY204 to CY207.

In embodiments, Formulae 201 and 202 may each not include groupsrepresented by Formulae CY201 to CY203.

In embodiments, Formulae 201 and 202 may each not include groupsrepresented by Formulae CY201 to CY203, and include at least one ofgroups represented by Formulae CY204 to CY217.

In embodiments, Formulae 201 and 202 may each not include groupsrepresented by Formulae CY201 to CY217.

In embodiments, the hole transport region may include one of CompoundsHT1 to HT46 and m-MTDATA, TDATA, 2-TNATA, NPB (NPD), β-NPB, TPD,spiro-TPD, spiro-NPB, methylated-NPB, TAPC, HMTPD,4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA),polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/camphorsulfonic acid (PANI/CSA),polyaniline/poly(4-styrenesulfonate (PANI/PSS), or any combinationthereof:

A thickness of the hole transport region may be in a range of about 50Angstroms (Å) to about 10,000 Å. For example, the thickness of the holetransport region may be in a range of about 100 Å to about 4,000 Å. Whenthe hole transport region includes a hole injection layer, a holetransport layer, or any combination thereof, a thickness of the holeinjection layer may be in a range of about 100 Å to about 9,000 Å, and athickness of the hole transport layer may be in a range of about 50 Å toabout 2,000 Å. For example, the thickness of the hole injection layermay be in a range of 100 Å to about 1,000 Å. For example, the thicknessof the hole transport layer may be in a range of about 100 Å to about1,500 Å. When the thicknesses of the hole transport region, the holeinjection layer, and the hole transport layer are within any of theseranges, excellent hole transport characteristics may be obtained withouta substantial increase in driving voltage.

The emission auxiliary layer may increase luminescence efficiency bycompensating for an optical resonance distance according to a wavelengthof light emitted by an emission layer. The electron blocking layer mayprevent leakage of electrons to a hole transport region from theemission layer. Materials that may be included in the hole transportregion may also be included in an emission auxiliary layer and anelectron blocking layer.

[p-Dopant]

The hole transport region may include a charge generating material aswell as the aforementioned materials to improve conductive properties ofthe hole transport region. The charge generating material may besubstantially homogeneously or non-homogeneously dispersed (for example,as a single layer consisting of charge generating material) in the holetransport region.

The charge generating material may include, for example, a p-dopant.

In embodiments, a lowest unoccupied molecular orbital (LUMO) energylevel of the p-dopant may be equal to or less than about −3.5 eV.

In embodiments, the p-dopant may include a quinone derivative, acompound containing a cyano group, a compound containing element EL1 andelement EL2, or any combination thereof.

Examples of the quinone derivative may include TCNQ, F4-TCNQ, and thelike.

Examples of the compound containing a cyano group include HAT-CN, acompound represented by Formula 221, and the like:

In Formula 221,

R₂₂₁ to R₂₂₃ may each independently be a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), and

at least one of R₂₂₁ to R₂₂₃ may each independently be: a C₃-C₆₀carbocyclic group or a C₁-C₆₀ heterocyclic group, substituted with acyano group; —F; —Cl; —Br; —I; a C₁-C₂₀ alkyl group substituted with acyano group, —F, —Cl, —Br, —I, or any combination thereof; or anycombination thereof.

In the compound containing element EL1 and element EL2, element EL1 maybe a metal, a metalloid, or a combination thereof, and element EL2 maybe a non-metal, a metalloid, or a combination thereof.

Examples of the metal may include an alkali metal (e.g., lithium (Li),sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), or the like); analkaline earth metal (e.g., beryllium (Be), magnesium (Mg), calcium(Ca), strontium (Sr), barium (Ba), or the like); a transition metal(e.g., titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V),niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten(W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium(Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni),palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), orthe like); a post-transition metal (e.g., zinc (Zn), indium (In), tin(Sn), or the like); a lanthanide metal (e.g., lanthanum (La), cerium(Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm),europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium(Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or thelike); and the like.

Examples of the metalloid may include silicon (Si), antimony (Sb),tellurium (Te), and the like.

Examples of the non-metal may include oxygen (O), a halogen (e.g., F,Cl, Br, I, and the like), and the like.

For example, the compound containing element EL1 and element EL2 mayinclude a metal oxide, a metal halide (e.g., metal fluoride, metalchloride, metal bromide, metal iodide, and the like), a metalloid halide(e.g., a metalloid fluoride, a metalloid chloride, a metalloid bromide,a metalloid iodide, and the like), a metal telluride, or any combinationthereof.

Examples of the metal oxide may include tungsten oxide (e.g., WO, W₂O₃,WO₂, WO₃, W₂O₅, and the like), vanadium oxide (e.g., VO, V₂O₃, VO₂,V₂O₅, and the like), molybdenum oxide (e.g., MoO, Mo₂O₃, MoO₂, MoO₃,Mo₂O₅, and the like), rhenium oxide (e.g., ReO₃ and the like), and thelike.

Examples of the metal halide may include an alkali metal halide, analkaline earth metal halide, a transition metal halide, apost-transition metal halide, a lanthanide metal halide, and the like.

Examples of the alkali metal halide may include LiF, NaF, KF, RbF, CsF,LiCl, NaCl, KCl, RbCl, CsCl, LiBr, NaBr, KBr, RbBr, CsBr, LiI, NaI, KI,RbI, CsI, and the like.

Examples of the alkaline earth metal halide may include BeF₂, MgF₂,CaF₂, SrF₂, BaF₂, BeCl₂, MgCl₂, CaCl₂), SrCl₂, BaCl₂, BeBr₂, MgBr₂,CaBr₂, SrBr₂, BaBr₂, BeI₂, MgI₂, CaI₂, SrI₂, BaI₂, and the like.

Examples of the transition metal halide may include titanium halide(e.g., TiF₄, TiCl₄, TiBr₄, TiI₄, and the like), zirconium halide (e.g.,ZrF₄, ZrCl₄, ZrBr₄, ZrI₄, and the like), hafnium halide (e.g., HfF₄,HfCl₄, HfBr₄, Hff₄, and the like), vanadium halide (e.g., VF₃, VCl₃,VBr₃, VI₃, and the like), niobium halide (e.g., NbF₃, NbCl₃, NbBr₃,NbI₃, and the like), tantalum halide (e.g., TaF₃, TaCl₃, TaBr₃, TaI₃,and the like), chromium halide (e.g., CrF₃, CrCl₃, CrBr₃, CrI₃, and thelike), molybdenum halide (e.g., MoF₃, MoCl₃, MoBr₃, MoI₃, and the like),tungsten halide (e.g., WF₃, WCl₃, WBr₃, WI₃, and the like), manganesehalide (e.g., MnF₂, MnCl₂, MnBr₂, MnI₂, and the like), technetium halide(e.g., TcF₂, TcCl₂, TcBr₂, TcJ₂, and the like), rhenium halide (e.g.,ReF₂, ReCl₂, ReBr₂, ReI₂, and the like), iron halide (e.g., FeF₂, FeCl₂,FeBr₂, FeI₂, and the like), ruthenium halide (e.g., RuF₂, RuCl₂, RuBr₂,RuI₂, and the like), osmium halide (e.g., OsF₂, OsCl₂, OsBr₂, OsI₂, andthe like), cobalt halide (e.g., CoF₂, CoCl₂, CoBr₂, Cob₂, and the like),rhodium halide (e.g., RhF₂, RhCl₂, RhBr₂, RhJ₂, and the like), iridiumhalide (e.g., IrF₂, IrCl₂, IrBr₂, IrI₂, and the like), nickel halide(e.g., NiF₂, NiCl₂, NiBr₂, NiI₂, and the like), palladium halide (e.g.,PdF₂, PdCl₂, PdBr₂, PdI₂, and the like), platinum halide (e.g., PtF₂,PtCl₂, PtBr₂, PtI₂, and the like), copper halide (e.g., CuF, CuCl, CuBr,CuI, and the like), silver halide (e.g., AgF, AgCl, AgBr, AgI, and thelike), gold halide (e.g., AuF, AuCl, AuBr, AuI, and the like), and thelike.

Examples of the post-transition metal halide may include zinc halide(e.g., ZnF₂, ZnCl₂, ZnBr₂, ZnI₂, and the like), indium halide (e.g.,InI₃ and the like), tin halide (e.g., SnI₂ and the like), and the like.

Examples of the lanthanide metal halide may include YbF, YbF₂, YbF₃,SmF₃, YbCl, YbCl₂, YbCl₃, SmCl₃, YbBr, YbBr₂, YbBr₃, SmBr₃, YbI, YbI₂,YbI₃, SmI₃, and the like.

Examples of the metalloid halide may include antimony halide (e.g.,SbCl₅ and the like) and the like.

Examples of the metal telluride may include an alkali metal telluride(e.g., Li₂Te, Na₂Te, K₂Te, Rb₂Te, Cs₂Te, and the like), an alkalineearth metal telluride (e.g., BeTe, MgTe, CaTe, SrTe, BaTe, and thelike), a transition metal telluride (e.g., TiTe₂, ZrTe₂, HfTe₂, V₂Te₃,Nb₂Te₃, Ta₂Te₃, Cr₂Te₃, Mo₂Te₃, W₂Te₃, MnTe, TcTe, ReTe, FeTe, RuTe,OsTe, CoTe, RhTe, IrTe, NiTe, PdTe, PtTe, Cu₂Te, CuTe, Ag₂Te, AgTe,Au₂Te, and the like), a post-transition metal telluride (e.g., ZnTe andthe like), a lanthanide metal telluride (e.g., LaTe, CeTe, PrTe, NdTe,PmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe, LuTe, and thelike), and the like.

[Emission Layer in Interlayer 130]

When the light-emitting device 10 is a full color light-emitting device,the emission layer may be patterned into a red emission layer, a greenemission layer, and/or a blue emission layer, according to a subpixel.In embodiments, the emission layer may have a stacked structure. Thestacked structure may include two or more layers selected from a redemission layer, a green emission layer, and a blue emission layer. Thetwo or more layers may directly contact each other. In embodiments, thetwo or more layers may be separated from each other. In embodiments, theemission layer may include two or more materials. The two or morematerials may include a red light-emitting material, a greenlight-emitting material, or a blue light-emitting material. The two ormore materials may be mixed with each other in a single layer. The twoor more materials mixed with each other in the single layer may emitwhite light.

The emission layer may include a host and a dopant. The dopant may be aphosphorescent dopant, a fluorescent dopant, or any combination thereof.

An amount of the dopant in the emission layer may be in a range of about0.01 parts to about 15 parts by weight based on 100 parts by weight ofthe host.

In embodiments, the emission layer may include a quantum dot.

The emission layer may include a delayed fluorescence material. Thedelayed fluorescence material may serve as a host or a dopant in theemission layer.

A thickness of the emission layer may be in a range of about 100 Å toabout 1,000 Å. In embodiments, the thickness of the emission layer maybe in a range of about 200 Å to about 600 Å. When the thickness of theemission layer is within any of these ranges, improved luminescencecharacteristics may be obtained without a substantial increase indriving voltage.

[Host]

The host may include a compound represented by Formula 301:

[Ar₃₀₁]_(xb11)-[(L₃₀₁)_(xb1)-R₃₀₁]_(xb21)  [Formula 301]

In Formula 301,

Ar₃O₁ and L₃₀₁ may each independently be a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a),

xb11 may be 1, 2, or 3,

xb1 may be an integer from 0 to 5,

R₃₀₁ may be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, a C₁-C₆₀ alkyl group unsubstituted orsubstituted with at least one R_(10a), a C₂-C₆₀ alkenyl groupunsubstituted or substituted with at least one R_(10a), a C₂-C₆₀ alkynylgroup unsubstituted or substituted with at least one R_(10a), a C₁-C₆₀alkoxy group unsubstituted or substituted with at least one R_(10a), aC₃-C₆₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂),—B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), or —P(═O)(Q₃₀₁)(Q₃₀₂), andR_(10a) may be understood by referring to the description of R_(10a)provided herein,

xb21 may be an integer from 1 to 5, and

Q₃₀₁ to Q₃₀₃ may independently each be understood by referring to thedescription of Q₁ provided herein.

In embodiments, when xb11 in Formula 301 is 2 or greater, at least twoAr₃O₁(s) may be bound via a single bond.

In embodiments, the host may include a compound represented by Formula301-1, a compound represented by Formula 301-2, or any combinationthereof:

In Formulae 301-1 and 301-2,

ring A₃₀₁ to ring A₃₀₄ may each independently be a C₃-C₆₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), and R_(10a) may be understood by referring to the descriptionof R_(10a) provided herein,

X₃₀₁ may be O, S, N-[(L₃₀₄)_(xb4)-R₃₀₄], C(R₃₀₄)(R₃₀₅), orSi(R₃₀₄)(R₃₀₅),

xb22 and xb23 may each independently be 0, 1, or 2,

L₃₀₁, xb1, and R₃₀₁ may respectively be understood by referring to thedescriptions of L₃₀₁, xb1, and R₃₀₁ provided herein,

L₃₀₂ to L₃₀₄ may each independently be understood by referring to thedescription of L₃₀₁ provided herein,

xb2 to xb4 may each independently be understood by referring to thedescription of xb1 provided herein, and

R₃₀₂ to R₃₀₅ and R₃₁₁ to R₃₁₄ may each independently be understood byreferring to the description of R₃₀₁ provided herein.

In embodiments, the host may include an alkaline earth-metal complex, apost-transitional metal complex, or any combination thereof. Forexample, the host may include a Be complex (e.g., Compound H55), a Mgcomplex, a Zn complex, or any combination thereof.

In embodiments, the host may include one of Compounds H1 to H124,9,10-di(2-naphthyl)anthracene (ADN),2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN),9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN),4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene(mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), or any combinationthereof:

[Phosphorescent Dopant]

The phosphorescent dopant may include the organometallic compoundrepresented by Formula 1.

In embodiments, the phosphorescent dopant may include at least onetransition metal as a center metal.

The phosphorescent dopant may include a monodentate ligand, a bidentateligand, a tridentate ligand, a tetradentate ligand, a pentadentateligand, a hexadentate ligand, or any combination thereof.

The phosphorescent dopant may be electrically neutral.

In embodiments, the phosphorescent dopant may include an organometalliccomplex represented by Formula 401:

In Formulae 401 and 402,

M may be transition metal (e.g., iridium (Ir), platinum (Pt), palladium(Pd), osmium (Os), titanium (Ti), gold (Au), hafnium (Hf), europium(Eu), terbium (Tb), rhodium (Rh), rhenium (Re), or thulium (Tm)),

L₄₀₁ may be a ligand represented by Formula 402, and xc1 may be 1, 2, or3, and when xc1 is 2 or greater, at least two L₄O₁(s) may be identicalto or different from each other,

L₄₀₂ may be an organic ligand, and xc2 may be an integer from 0 to 4,and when xc2 is 2 or greater, at least two L₄O₂(s) may be identical toor different from each other,

X₄₀₁ and X₄O₂ may each independently be nitrogen (N) or carbon (C),

ring A₄₀₁ and ring A₄₀₂ may each independently be a C₃-C₆₀ carbocyclicgroup or a C₁-C₆₀ heterocyclic group,

T₄₀₁ may be a single bond, *—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q₄₁)-*′,*—C(Q₄₁₁)(Q₄₁₂)-*′, *—C(Q₄₁₁)=C(Q₄₁₂)-*′, *—C(Q₄₁₁)=*′, or *═C═*′,

X₄₀₃ and X₄O₄ may each independently be a chemical bond (e.g., acovalent bond or a coordinate bond), O, S, N(Q₄₁₃), B(Q₄₁₃), P(Q₄₁₃),C(Q₄₁₃)(Q₄₁₄), or Si(Q₄₁₃)(Q₄₁₄), and * and each indicate a binding siteto a neighboring atom,

Q₄₁₁ to Q₄₁₄ may each independently be understood by referring to thedescription of Q₁ provided herein,

R₄₀₁ and R₄₀₂ may each independently be hydrogen, deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₂₀ alkylgroup unsubstituted or substituted with at least one R_(10a), a C₁-C₂₀alkoxy group unsubstituted or substituted with at least one R_(10a), aC₃-C₆₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), —Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂),—B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), or —P(═O)(Q₄₀₁)(Q₄₀₂), andR_(10a) may be understood by referring to the description of R_(10a)provided herein,

Q₄₀₁ to Q₄₀₃ may each independently be understood by referring to thedescription of Q₁ provided herein,

xc11 and xc12 may each independently be an integer from 0 to 10, and

* and *′ in Formula 402 each indicate a binding site to M in Formula401.

In embodiments, in Formula 402, X₄₀₁ may be nitrogen and X₄₀₂ may becarbon, or X₄₀₁ and X₄₀₂ may both be nitrogen.

In embodiments, when xc1 in Formula 401 is 2 or greater, two ringA₄₀₁(s) of at least two L₄₀₁(s) may optionally be bound via T₄₀₂ as alinking group, or two ring A₄₀₂(s) may optionally be bound via T₄₀₃ as alinking group (see Compounds PD1 to PD4 and PD7). T₄₀₂ and T₄₀₃ may eachindependently be understood by referring to the description of T₄₀₁provided herein.

L₄₀₂ in Formula 401 may be any suitable organic ligand. For example,L₄₀₂ may be a halogen group, a diketone group (e.g., an acetylacetonategroup), a carboxylic acid group (e.g., a picolinate group), —C(═O), anisonitrile group, —CN, or a phosphorus group (e.g., a phosphine group ora phosphite group).

The phosphorescent dopant may be, for example, one of Compounds PD1 toPD25 or any combination thereof.

[Fluorescent Dopant]

The fluorescent dopant may include an amine group-containing compound, astyryl group-containing compound, or any combination thereof.

In embodiments, the fluorescent dopant may include a compoundrepresented by Formula 501:

In Formula 501,

Ar₅₀₁, L₅₀₁ to L₅₀₃, R₅₀₁, and R₅₀₂ may each independently be a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a),

xd1 to xd3 may each independently be 0, 1, 2, or 3, and

xd4 may be 1, 2, 3, 4, 5, or 6.

In embodiments, in Formula 501, Ar_(50i) may include a condensed ringgroup (e.g., an anthracene group, a chrysene group, or a pyrene group)in which at least three monocyclic groups are condensed.

In embodiments, xd4 in Formula 501 may be 2.

In embodiments, the fluorescent dopant may include one of Compounds FD1to FD36, DPVBi, DPAVBi, or any combination thereof.

[Delayed Fluorescence Material]

The emission layer may include a delayed fluorescence material.

The delayed fluorescence material described herein may be any suitablecompound that may emit delayed fluorescence according to a delayedfluorescence emission mechanism.

The delayed fluorescence material included in the emission layer mayserve as a host or a dopant, depending on types of other materialsincluded in the emission layer.

In embodiments, a difference between a triplet energy level in electronvolts (eV) of the delayed fluorescence material and a singlet energylevel in electron volts (eV) of the delayed fluorescence material may bein a range of about 0 eV to about 0.5 eV. When the difference between atriplet energy level in electron volts (eV) of the delayed fluorescencematerial and a singlet energy level in electron volts (eV) of thedelayed fluorescence material is within this range, up-conversion from atriplet state to a singlet state in the delayed fluorescence materialmay effectively occur, thus improving luminescence efficiency and thelike of the light-emitting device 10.

In embodiments, the delayed fluorescence material may include: amaterial including at least one electron donor (e.g., a π electron-richC₃-C₆₀ cyclic group such as a carbazole group and the like) and at leastone electron acceptor (e.g., a sulfoxide group, a cyano group, a πelectron-deficient nitrogen-containing C₁-C₆₀ cyclic group, and thelike), a material including a C₈-C₆₀ polycyclic group including at leasttwo cyclic groups condensed to each other and sharing boron (B), and thelike.

Examples of the delayed fluorescence material may include at least oneof Compounds DF1 to DF9:

[Quantum Dots]

The emission layer may include quantum dots.

The term “quantum dot” as used herein may be a crystal of asemiconductor compound and may include any suitable material capable ofemitting emission wavelengths of various lengths according to the sizeof the crystal.

A diameter of the quantum dot may be, for example, in a range of about 1nm to about 10 nm.

Quantum dots may be synthesized by a wet chemical process, a metalorganic chemical vapor deposition process, a molecular beam epitaxyprocess, or any similar process.

The wet chemical process is a method of growing a quantum dot particlecrystal by mixing a precursor material with an organic solvent. When thecrystal grows, the organic solvent may naturally serve as a dispersantcoordinated on the surface of the quantum dot crystal and control thegrowth of the crystal. Thus, the wet chemical method may be easier toperform than the vapor deposition process such a metal organic chemicalvapor deposition (MOCVD) or a molecular beam epitaxy (MBE) process.Further, the growth of quantum dot particles may be controlled with alower manufacturing cost.

The quantum dot may include a Group II-VI semiconductor compound; aGroup III-V semiconductor compound; a Group III-VI semiconductorcompound; a Group I-III-VI semiconductor compound; a Group IV-VIsemiconductor compound; a Group IV element or compound; or anycombination thereof.

Examples of the Group II-VI semiconductor compound may include a binarycompound such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe,MgSe, or MgS; a ternary compound such as CdSeS, CdSeTe, CdSTe, ZnSeS,ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS,CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, or MgZnS; a quaternarycompound such as CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe,HgZnSeS, HgZnSeTe, or HgZnSTe; or any combination thereof.

Examples of the Group III-V semiconductor compound may include a binarycompound such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP,InAs, or InSb; a ternary compound such as GaNP, GaNAs, GaNSb, GaPAs,GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InAIP, InNAs,InNSb, InPAs, or InPSb; a quaternary compound such as GaAlNP, GaAlNAs,GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb,InAlNP, InAlNAs, InAlNSb, InAlPAs, or InAlPSb; or any combinationthereof. In embodiments, the Group III-V semiconductor compound mayfurther include a Group II element. Examples of the Group III-Vsemiconductor compound further including a Group II element may includeInZnP, InGaZnP, InAlZnP, and the like.

Examples of the Group III-VI semiconductor compound may include a binarycompound such as GaS, GaSe, Ga₂Se₃, GaTe, InS, InSe, In₂S₃, In₂Se₃,InTe, and the like; a ternary compound such as InGaS₃, InGaSe₃, and thelike; or any combination thereof.

Examples of the Group I-III-VI semiconductor compound may include aternary compound such as AgInS, AgInS₂, CuInS, CuInS₂, CuGaO₂, AgGaO₂,AgAlO₂, or any combination thereof.

Examples of the Group IV-VI semiconductor compound may include a binarycompound such as SnS, SnSe, SnTe, PbS, PbSe, or PbTe; a ternary compoundsuch as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, orSnPbTe; a quaternary compound such as SnPbSSe, SnPbSeTe, or SnPbSTe; orany combination thereof.

The Group IV element or compound may be a single element material suchas Si or Ge; a binary compound such as SiC or SiGe; or any combinationthereof.

Individual elements included in the multi-element compound, such as abinary compound, a ternary compound, and a quaternary compound, may bepresent in a particle thereof at a uniform or at a non-uniformconcentration.

The quantum dot may have a single structure in which the concentrationof each element included in the quantum dot is uniform or a core-shelldouble structure. In embodiments, materials included in the core may bedifferent from materials included in the shell.

The shell of the quantum dot may be a protective layer that preventschemical denaturation of the core to maintain semiconductorcharacteristics and/or may be a charging layer that impartselectrophoretic characteristics to the quantum dot. The shell may be amonolayer or a multilayer. An interface between a core and a shell mayhave a concentration gradient where a concentration of elements presentin the shell decreases toward the core.

Examples of the shell of the quantum dot may include a metal oxide, ametalloid oxide, a nonmetal oxide, a semiconductor compound, or acombination thereof. Examples of the metal oxide, the metalloid oxide,or the nonmetal oxide may include a binary compound such as SiO₂, Al₂O₃,TiO₂, ZnO, MnO, Mn₂O₃, Mn₃O₄, CuO, FeO, Fe₂O₃, Fe₃O₄, CoO, Co₃O₄, orNiO; a ternary compound such as MgAl₂O₄, CoFe₂O₄, NiFe₂O₄, or CoMn₂O₄;or any combination thereof. Examples of the semiconductor compound mayinclude a Group II-VI semiconductor compound; a Group III-Vsemiconductor compound; a Group III-VI semiconductor compound; a GroupI-III-VI semiconductor compound; a Group IV-VI semiconductor compound;or any combination thereof. In embodiments, the semiconductor compoundmay be CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb,HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, or anycombination thereof.

The quantum dot may have a full width of half maximum (FWHM) of aspectrum of an emission wavelength equal to or less than about 45 nm.For example, the quantum dot may have a FWHM of a spectrum of anemission wavelength equal to or less than about 40 nm. For example, thequantum dot may have a FWHM of a spectrum of an emission wavelengthequal to or less than about 30 nm. When the FWHM of the quantum dot iswithin any of the above ranges, color purity or color reproducibilitymay be improved. Light emitted through the quantum dots may be emittedin all directions, and an optical viewing angle may be improved.

The quantum dot may be a spherical particle, a pyramidal particle, amulti-arm particle, a cubic nanoparticle, a nanotube, a nanowire, ananofiber, or a nanoplate.

By adjusting the size of the quantum dot, the energy band gap may alsobe adjusted, thereby obtaining light of various wavelengths in thequantum dot emission layer. By using quantum dots of various sizes, alight-emitting device that may emit light of various wavelengths may berealized. In embodiments, the size of the quantum dot may be selectedsuch that the quantum dot may emit red, green, and/or blue light. Thesize of the quantum dot may be selected such that the quantum dot mayemit white light by combining various light colors.

[Electron Transport Region in Interlayer 130]

The electron transport region may have a structure consisting of a layerconsisting of a single material, a structure consisting of a layerincluding different materials, or a multi-layered structure havinglayers including different materials.

The electron transport region may include a buffer layer, a holeblocking layer, an electron control layer, an electron transport layer,or an electron injection layer.

In embodiments, the electron transport region may have an electrontransport layer/electron injection layer structure, a hole blockinglayer/electron transport layer/electron injection layer structure, anelectron control layer/electron transport layer/electron injection layerstructure, or a buffer layer/electron transport layer/electron injectionlayer structure, wherein layers of each structure may be stacked on theemission layer in its respective stated order, but embodiments are notlimited thereto.

The electron transport region (e.g., a buffer layer, a hole blockinglayer, an electron control layer, or an electron transport layer in theelectron transport region) may include a metal-free compound includingat least one π electron-deficient nitrogen-containing C₁-C₆₀ cyclicgroup.

In embodiments, the electron transport region may include a compoundrepresented by Formula 601:

[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21)  [Formula 601]

In Formula 601,

Ar₆₀₁ and L₆₀₁ may each independently be a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a),

xe11 may be 1, 2, or 3,

xe1 may be 0, 1, 2, 3, 4, or 5,

R_(6o1) may be a C₃-C₆₀ carbocyclic group unsubstituted or substitutedwith at least one R_(10a), a C₁-C₆₀ heterocyclic group unsubstituted orsubstituted with at least one R_(10a), —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃),—C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), or —P(═O)(Q₆₀₁)(Q₆₀₂),

Q₆₀₁ to Q₆₀₃ may each independently be understood by referring to thedescription of Q₁ provided herein,

xe21 may be 1, 2, 3, 4, or 5, and

at least one of Ar₆₀₁, L₆₀₁, and R₆₀₁ may each independently be a πelectron-deficient nitrogen-containing C₁-C₆₀ cyclic group unsubstitutedor substituted with at least one R_(10a), and R_(10a) may be understoodby referring to the description of R_(10a) provided herein.

In embodiments, when xe11 in Formula 601 is 2 or greater, at least twoAr₆₀₁(s) may be bound via a single bond.

In embodiments, in Formula 601, Ar₆₀₁ may be a substituted orunsubstituted anthracene group.

In embodiments, the electron transport region may include a compoundrepresented by Formula 601-1:

In Formula 601-1,

X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), X₆₁₆ may be N orC(R₆₁₆), and at least one of X₆₁₄ to X₆₁₆ may be N,

L₆₁₁ to L₆₁₃ may each independently be understood by referring to thedescription of L₆₀₁ provided herein,

xe611 to xe613 may each independently be understood by referring to thedescription of xe1 provided herein,

R_(61n) to R_(61i) may each independently be understood by referring tothe description of R_(6oi) provided herein, and

R₆₁₄ to R₆₁₆ may each independently be hydrogen, deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₂₀ alkylgroup, a C₁-C₂₀ alkoxy group, a C₃-C₆₀ carbocyclic group unsubstitutedor substituted with at least one R_(10a), or a C₁-C₆₀ heterocyclic groupunsubstituted or substituted with at least one R_(10a), and R_(10a) maybe understood by referring to the description of R_(10a) providedherein.

For example, in Formulae 601 and 601-1, xe1 and xe611 to xe613 may eachindependently be 0, 1, or 2.

The electron transport region may include one of Compounds ET1 to ET45,2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP),4,7-diphenyl-1,10-phenanthroline (Bphen), Alq₃, BAlq, TAZ, NTAZ, or anycombination thereof:

A thickness of the electron transport region may be in a range of about100 Angstroms (k) to about 5,000 k. For example, the thickness of theelectron transport region may be in a range of about 100 Å to about4,000 Å. When the electron transport region includes a buffer layer, ahole blocking layer, an electron control layer, an electron transportlayer, or any combination thereof, a thickness of the buffer layer, thehole blocking layer, or the electron control layer may eachindependently be in a range of about 20 Å to about 1,000 Å, and athickness of the electron transport layer may be in a range of about 100Å to about 1,000 Å. For example, the thickness of the buffer layer, thehole blocking layer, or the electron control layer may eachindependently be in a range of about 30 Å to about 300 Å. For example,the thickness of the electron transport layer may be in a range of about150 Å to about 500 Å. When the thicknesses of the buffer layer, the holeblocking layer, the electron control layer, and/or the electrontransport layer are each within these ranges, excellent electrontransport characteristics may be obtained without a substantial increasein driving voltage.

The electron transport region (for example, the electron transport layerin the electron transport region) may further include, in addition tothe materials described above, a metal-containing material.

The metal-containing material may include an alkali metal complex, analkaline earth metal complex, or any combination thereof. A metal ion ofthe alkali metal complex may be a lithium (Li) ion, a sodium (Na) ion, apotassium (K) ion, a rubidium (Rb) ion, or a cesium (Cs) ion. A metalion of the alkaline earth metal complex may be a beryllium (Be) ion, amagnesium (Mg) ion, a calcium (Ca) ion, a strontium (Sr) ion, or abarium (Ba) ion. A ligand coordinated with the metal ion of the alkalimetal complex and the alkaline earth metal complex may eachindependently be hydroxyquinoline, hydroxyisoquinoline,hydroxybenzoquinoline, hydroxyacridine, hydroxyphenanthridine,hydroxyphenyloxazole, hydroxyphenylthiazole, hydroxyphenyloxadiazole,hydroxyphenylthiadiazole, hydroxyphenylpyridine,hydroxyphenylbenzimidazole, hydroxyphenylbenzothiazole, bipyridine,phenanthroline, cyclopentadiene, or any combination thereof.

For example, the metal-containing material may include a Li complex. TheLi complex may include, e.g., Compound ET-D1 (LiQ) or Compound ET-D2:

The electron transport region may include an electron injection layerthat facilitates injection of electrons from the second electrode 150.The electron injection layer may directly contact the second electrode150.

The electron injection layer may have a structure consisting of a layerconsisting of a single material, a structure consisting of a layerincluding different materials, or a multi-layered structure havinglayers including different materials.

The electron injection layer may include an alkali metal, an alkalineearth metal, a rare earth metal, an alkali metal-containing compound, analkaline earth metal-containing compound, a rare earth metal-containingcompound, an alkali metal complex, an alkaline earth metal complex, arare earth metal complex, or any combination thereof.

The alkali metal may be Li, Na, K, Rb, Cs or any combination thereof.The alkaline earth metal may be Mg, Ca, Sr, Ba, or any combinationthereof. The rare earth metal may be Sc, Y, Ce, Tb, Yb, Gd, or anycombination thereof.

The alkali metal-containing compound, the alkaline earthmetal-containing compound, and the rare earth metal-containing compoundmay respectively be oxides, halides (e.g., fluorides, chlorides,bromides, or iodides), tellurides, or any combination thereof of each ofthe alkali metal, the alkaline earth metal, and the rare earth metal.

The alkali metal-containing compound may be alkali metal oxides such asLi₂O, Cs₂O, or K₂O, alkali metal halides such as LiF, NaF, CsF, KF, LiI,NaI, CsI, or KI, or any combination thereof. The alkalineearth-metal-containing compound may include alkaline earth-metal oxides,such as BaO, SrO, CaO, Ba_(x)Sr_(1-x)O (wherein x is a real numbersatisfying 0<x<1), or Ba_(x)Ca_(1-x)O (wherein x is a real numbersatisfying 0<x<1). The rare earth metal-containing compound may includeYbF₃, ScF₃, Sc₂O₃, Y₂O₃, Ce₂O₃, GdF₃, TbF₃, YbI₃, ScI₃, TbI₃, or anycombination thereof. In embodiments, the rare earth metal-containingcompound may include a lanthanide metal telluride. Examples of thelanthanide metal telluride may include LaTe, CeTe, PrTe, NdTe, PmTe,SmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe, LuTe, La₂Te₃,Ce₂Te₃, Pr₂Te₃, Nd₂Te₃, Pm₂Te₃, Sm₂Te₃, Eu₂Te₃, Gd₂Te₃, Tb₂Te₃, Dy₂Te₃,Ho₂Te₃, Er₂Te₃, Tm₂Te₃, Yb₂Te₃, Lu₂Te₃, and the like.

The alkali metal complex, the alkaline earth metal complex, and the rareearth metal complex may include one of ions of the alkali metal, ions ofthe alkaline earth metal, and ions of the rare earth metal describedabove, and a ligand bonded to the metal ion, e.g., hydroxyquinoline,hydroxyisoquinoline, hydroxybenzoquinoline, hydroxyacridine,hydroxyphenanthridine, hydroxyphenyloxazole, hydroxyphenylthiazole,hydroxyphenyloxadiazole, hydroxyphenylthiadiazole,hydroxyphenylpyridine, hydroxyphenylbenzimidazole,hydroxyphenylbenzothiazole, bipyridine, phenanthroline, cyclopentadiene,or any combination thereof.

The electron injection layer may consist of an alkali metal, an alkalineearth metal, a rare earth metal, an alkali metal-containing compound, analkaline earth metal-containing compound, a rare earth metal-containingcompound, an alkali metal complex, an alkaline earth metal complex, arare earth metal complex, or any combination thereof, as describedabove. In embodiments, the electron injection layer may further includean organic material (e.g., a compound represented by Formula 601).

In embodiments, the electron injection layer may consist of an alkalimetal-containing compound (e.g., alkali metal halide); or an alkalimetal-containing compound (e.g., alkali metal halide), and an alkalimetal, an alkaline earth metal, a rare earth metal, or any combinationthereof. In embodiments, the electron injection layer may be a KI:Ybco-deposition layer, a RbI:Yb co-deposition layer, and the like.

When the electron injection layer further includes an organic material,the alkali metal, the alkaline earth metal, the rare earth metal, thealkali metal-containing compound, the alkaline earth metal-containingcompound, the rare earth metal-containing compound, the alkali metalcomplex, the alkaline earth metal complex, the rare earth metal complex,or any combination thereof may be homogeneously or non-homogeneouslydispersed in a matrix including the organic material.

A thickness of the electron injection layer may be in a range of about 1Å to about 100 Å. For example, the thickness of the electron injectionlayer may be in a range of about 3 Å to about 90 Å. When the thicknessof the electron injection layer is within any of these ranges, excellentelectron injection characteristics may be obtained without a substantialincrease in driving voltage.

[Second Electrode 150]

The second electrode 150 may be on the interlayer 130. In an embodiment,the second electrode 150 may be a cathode that is an electron injectionelectrode, and a material for forming the second electrode 150 may be amaterial having a low work function, such as a metal, an alloy, anelectrically conductive compound, or any combination thereof.

The second electrode 150 may include lithium (Li), silver (Ag),magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca),magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ytterbium (Yb),silver-ytterbium (Ag—Yb), ITO, IZO, or any combination thereof. Thesecond electrode 150 may be a transmissive electrode, a transflectiveelectrode, or a reflective electrode.

The second electrode 150 may have a single-layered structure, or amulti-layered structure including two or more layers.

[Capping Layer]

A first capping layer may be located outside the first electrode 110,and/or a second capping layer may be located outside the secondelectrode 150. In embodiments, the light-emitting device 10 may have astructure in which the first capping layer, the first electrode 110, theinterlayer 130, and the second electrode 150 are stacked in this statedorder, a structure in which the first electrode 110, the interlayer 130,the second electrode 150, and the second capping layer are stacked inthis stated order, or a structure in which the first capping layer, thefirst electrode 110, the interlayer 130, the second electrode 150, andthe second capping layer are stacked in this stated order.

In the light-emitting device 10, light emitted from the emission layerin the interlayer 130 may pass through the first electrode 110 (whichmay be a transflective electrode or a transmissive electrode) andthrough the first capping layer to the outside. In the light-emittingdevice 10, light emitted from the emission layer in the interlayer 130may pass through the second electrode 150 (which may be a transflectiveelectrode or a transmissive electrode) and through the second cappinglayer to the outside.

The first capping layer and the second capping layer may each improvethe external luminescence efficiency based on the principle ofconstructive interference. Accordingly, the optical extractionefficiency of the light-emitting device 10 may be increased, thusimproving the luminescence efficiency of the light-emitting device 10.

The first capping layer and the second capping layer may each include amaterial having a refractive index equal to or greater than about 1.6(at a wavelength of about 589 nm).

The first capping layer and the second capping layer may eachindependently be an organic capping layer including an organic material,an inorganic capping layer including an inorganic material, or anorganic-inorganic composite capping layer including an organic materialand an inorganic material.

At least one of the first capping layer and the second capping layer mayeach independently include carbocyclic compounds, heterocycliccompounds, amine group-containing compounds, porphine derivatives,phthalocyanine derivatives, naphthalocyanine derivatives, alkali metalcomplexes, alkaline earth metal complexes, or any combination thereof.The carbocyclic compound, the heterocyclic compound, and the aminegroup-containing compound may each independently be optionallysubstituted with a substituent including O, N, S, Se, Si, F, Cl, Br, I,or any combination thereof. In embodiments, at least one of the firstcapping layer and the second capping layer may each independentlyinclude an amine group-containing compound.

In embodiments, at least one of the first capping layer and the secondcapping layer may each independently include the compound represented byFormula 201, the compound represented by Formula 202, or any combinationthereof.

In embodiments, at least one of the first capping layer and the secondcapping layer may each independently include one of Compounds HT28 toHT33, one of Compounds CP1 to CP6, β-NPB, or any combination thereof.

[Film]

The organometallic compound represented by Formula 1 may be included invarious films. According to embodiments, a film including anorganometallic compound represented by Formula 1 may be provided. Thefilm may be, for example, an optical member (or a light-controllingmember) (e.g., a color filter, a color-conversion member, a cappinglayer, a light extraction efficiency improvement layer, a selectivelight-absorbing layer, a polarization layer, a quantum dot-containinglayer, or the like), a light-blocking member (e.g., a light reflectionlayer or a light-absorbing layer), or a protection member (e.g., aninsulating layer or a dielectric material layer).

[Electronic Apparatus]

The light-emitting device may be included in various electronicapparatuses. In embodiments, an electronic apparatus including thelight-emitting device may be an emission apparatus or an authenticationapparatus.

The electronic apparatus (e.g., an emission apparatus) may furtherinclude, in addition to the light-emitting device, a color filter, acolor-conversion layer, or a color filter and a color-conversion layer.The color filter and/or the color-conversion layer may be disposed on atleast one traveling direction of light emitted from the light-emittingdevice. For example, light emitted from the light-emitting device may beblue light or white light. The light-emitting device may be understoodby referring to the descriptions provided herein. In embodiments, thecolor-conversion layer may include quantum dots. The quantum dot may be,for example, the quantum dot described herein.

The electronic apparatus may include a first substrate. The firstsubstrate may include subpixels, the color filter may include colorfilter areas respectively corresponding to the subpixels, and thecolor-conversion layer may include color-conversion areas respectivelycorresponding to the subpixels.

A pixel-defining film may be located between the subpixels to defineeach subpixel.

The color filter may further include color filter areas andlight-blocking patterns between the color filter areas, and thecolor-conversion layer may further include color-conversion areas andlight-blocking patterns between the color-conversion areas.

The color filter areas (or the color-conversion areas) may include afirst area emitting first color light, a second area emitting secondcolor light, and/or a third area emitting third color light, and thefirst color light, the second color light, and/or the third color lightmay have different maximum emission wavelengths from one another. Inembodiments, the first color light may be red light, the second colorlight may be green light, and the third color light may be blue light.In embodiments, the color filter areas (or the color-conversion areas)may each include quantum dots. In embodiments, the first area mayinclude red quantum dots, the second area may include green quantumdots, and the third area may not include a quantum dot. The quantum dotmay be understood by referring to the description of the quantum dotprovided herein. The first area, the second area, and/or the third areamay each further include a scatterer.

In embodiments, the light-emitting device may emit first light, thefirst area may absorb the first light to emit 1-1 color light, thesecond area may absorb the first light to emit 2-1 color light, and thethird area may absorb the first light to emit 3-1 color light. In thisembodiment, the 1-1 color light, the 2-1 color light, and the 3-1 colorlight may each have a different maximum emission wavelength from oneanother. In embodiments, the first light may be blue light, the 1-1color light may be red light, the 2-1 color light may be green light,and the 3-1 color light may be blue light.

The electronic apparatus may further include a thin-film transistor, inaddition to the light-emitting device. The thin-film transistor mayinclude a source electrode, a drain electrode, and an active layer,wherein one of the source electrode and the drain electrode may beelectrically connected to one of the first electrode and the secondelectrode of the light-emitting device.

The thin-film transistor may further include a gate electrode, a gateinsulating film, or the like.

The active layer may include a crystalline silicon, an amorphoussilicon, an organic semiconductor, and an oxide semiconductor.

The electronic apparatus may further include an encapsulation unit forsealing the light-emitting device. The encapsulation unit may be locatedbetween the color filter and/or the color-conversion layer and thelight-emitting device. The encapsulation unit may allow light to pass tothe outside from the light-emitting device and may prevent air and/ormoisture from permeating into the light-emitting device at the sametime. The encapsulation unit may be a sealing substrate includingtransparent glass or a plastic substrate. The encapsulation unit may bea thin-film encapsulating layer including at least one of an organiclayer and an inorganic layer. When the encapsulation unit is a thin-filmencapsulating layer, the electronic apparatus may be flexible.

In addition to the color filter and/or the color-conversion layer,various functional layers may be disposed on the encapsulation unitdepending on the use of an electronic apparatus. Examples of thefunctional layer may include a touch screen layer, a polarization layer,an authentication apparatus, or the like. The touch screen layer may bea resistive touch screen layer, a capacitive touch screen layer, or aninfrared beam touch screen layer. The authentication apparatus may be,for example, a biometric authentication apparatus that identifies anindividual according to biometric information (e.g., a fingertip, apupil, or the like).

The authentication apparatus may further include a biometric informationcollecting unit, in addition to the light-emitting device describedabove.

The electronic apparatus may be applicable to various displays, such asan optical source, lighting, a personal computer (e.g., a mobilepersonal computer), a cellphone, a digital camera, an electronic note,an electronic dictionary, an electronic game console, a medical device(e.g., an electronic thermometer, a blood pressure meter, a glucometer,a pulse measuring device, a pulse wave measuring device, anelectrocardiograph recorder, an ultrasonic diagnosis device, or anendoscope display device), a fish finder, various measurement devices,gauges (e.g., gauges of an automobile, an airplane, or a ship), and aprojector.

[Descriptions of FIGS. 2 and 3]

FIG. 2 is a schematic cross-sectional view of an electronic apparatusaccording to an embodiment.

An electronic apparatus in FIG. 2 may include a substrate 100, athin-film transistor, a light-emitting device, and an encapsulation unit300 sealing the light-emitting device.

The substrate 100 may be a flexible substrate, a glass substrate, or ametal substrate. A buffer layer 210 may be on the substrate 100. Thebuffer layer 210 may prevent penetration of impurities through thesubstrate 100 and provide a flat surface on the substrate 100.

A thin-film transistor may be on the buffer layer 210. The thin-filmtransistor may include an active layer 220, a gate electrode 240, asource electrode 260, and a drain electrode 270.

The active layer 220 may include an inorganic semiconductor such assilicon or polysilicon, an organic semiconductor, or an oxidesemiconductor and include a source area, a drain area, and a channelarea.

A gate insulating film 230 for insulating the active layer 220 and thegate electrode 240 may be on the active layer 220, and the gateelectrode 240 may be on the gate insulating film 230.

An interlayer insulating film 250 may be on the gate electrode 240. Theinterlayer insulating film 250 may be between the gate electrode 240 andthe source electrode 260 and between the gate electrode 240 and thedrain electrode 270 to provide insulation therebetween.

The source electrode 260 and the drain electrode 270 may be on theinterlayer insulating film 250. The interlayer insulating film 250 andthe gate insulating film 230 may be formed to expose the source area andthe drain area of the active layer 220, and the source electrode 260 andthe drain electrode 270 may be adjacent to the exposed source area andthe exposed drain area of the active layer 220.

Such a thin-film transistor may be electrically connected to alight-emitting device to drive the light-emitting device and may beprotected by a passivation layer 280. The passivation layer 280 mayinclude an inorganic insulating film, an organic insulating film, or acombination thereof. A light-emitting device may be on the passivationlayer 280. The light-emitting device may include a first electrode 110,an interlayer 130, and a second electrode 150.

The first electrode 110 may be on the passivation layer 280. Thepassivation layer 280 may not fully cover the drain electrode 270 andexpose a specific area of the drain electrode 270, and the firstelectrode 110 may be disposed to electrically connect to the exposedarea of the drain electrode 270.

A pixel-defining film 290 may be on the first electrode 110. Thepixel-defining film 290 may expose a specific area of the firstelectrode 110, and the interlayer 130 may be formed in the exposed area.The pixel-defining film 290 may be a polyimide or polyacryl organicfilm. Although it is not shown in FIG. 2, some higher layers of theinterlayer 130 may extend to the upper portion of the pixel-definingfilm 290 and may be disposed in the form of a common layer.

The second electrode 150 may be on the interlayer 130, and a cappinglayer 170 may be additionally formed on the second electrode 150. Thecapping layer 170 may be formed to cover the second electrode 150.

The encapsulation unit 300 may be on the capping layer 170. Theencapsulation unit 300 may be on the light-emitting device to protect alight-emitting device from moisture and/or oxygen. The encapsulationunit 300 may include an inorganic film including silicon nitride(SiN_(x)), silicon oxide (SiO_(x)), indium tin oxide, indium zinc oxide,or any combination thereof, an organic film including PET, polyethylenenaphthalate, polycarbonate, polyimide, polyethylene sulfonate, polyoxymethylene, polyaryllate, hexamethyl disiloxane, an acrylic based resin(e.g., polymethyl methacrylate, polyacrylic acid, and the like), anepoxy based resin (e.g., aliphatic glycidyl ether (AGE) and the like),or any combination thereof; or a combination of the inorganic film andthe organic film.

FIG. 3 is a schematic cross-sectional view of an electronic apparatusaccording to an embodiment.

The electronic apparatus shown in FIG. 3 may be substantially identicalto the electronic apparatus shown in FIG. 2, except that alight-blocking pattern 500 and a functional area 400 are additionallylocated on the encapsulation unit 300. The functional area 400 may be acolor filter area, a color-conversion area, or a combination of a colorfilter area and a color-conversion area. In embodiments, thelight-emitting device included in the electronic apparatus shown in FIG.3 may be a tandem light-emitting device.

[Manufacturing Method]

The layers constituting the hole transport region, the emission layer,and the layers constituting the electron transport region may be formedin a specific region by using one or more suitable methods such asvacuum deposition, spin coating, casting, Langmuir-Blodgett (LB)deposition, ink-jet printing, laser printing, and laser-induced thermalimaging.

When layers constituting the hole transport region, an emission layer,and layers constituting the electron transport region are eachindependently formed by vacuum-deposition, the vacuum-deposition may beperformed at a deposition temperature in a range of about 100° C. toabout 500° C., at a vacuum degree in a range of about 10⁻⁸ torr to about10⁻³ torr, and at a deposition rate in a range of about 0.01 Angstromsper second (A/sec) to about 100 Å/sec, depending on the material to beincluded in each layer and the structure of each layer to be formed.

Definitions of Terms

The term “C₃-C₆₀ carbocyclic group” as used herein may be a cyclic groupconsisting only of carbon atoms as ring-forming atoms and having 3 to 60carbon atoms as ring-forming atoms. The term “C₁-C₆₀ heterocyclic group”as used herein may be a cyclic group having 1 to 60 carbon atoms inaddition to at least one heteroatom as ring-forming atoms other thancarbon atoms. The C₃-C₆₀ carbocyclic group and the C₁-C₆₀ heterocyclicgroup may each be a monocyclic group consisting of one ring or apolycyclic group in which at least two rings are condensed. For example,the number of ring-forming atoms in a C₁-C₆₀ heterocyclic group may bein a range of 3 to 61.

The term “cyclic group” as used herein may include the C₃-C₆₀carbocyclic group and the C₁-C₆₀ heterocyclic group.

The term “n electron-rich C₃-C₆₀ cyclic group” as used herein may be acyclic group having 3 to 60 carbon atoms and not including *—N=*′ as aring-forming moiety. The term “R electron-deficient nitrogen-containingC₁-C₆₀ cyclic group” as used herein may be a heterocyclic group having 1to 60 carbon atoms and may include *—N=*′ as a ring-forming moiety.

In embodiments,

the C₃-C₆₀ carbocyclic group may be a T1 group or a group in which atleast two T1 groups are condensed (for example, a cyclopentadiene group,an adamantane group, a norbornane group, a benzene group, a pentalenegroup, a naphthalene group, an azulene group, an indacene group, anacenaphthylene group, a phenalene group, a phenanthrene group, ananthracene group, a fluoranthene group, a triphenylene group, a pyrenegroup, a chrysene group, a perylene group, a pentaphene group, aheptalene group, a naphthacene group, a picene group, a hexacene group,a pentacene group, a rubicene group, a coronene group, an ovalene group,an indene group, a fluorene group, a spiro-bifluorene group, abenzofluorene group, an indenophenanthrene group, or an indenoanthracenegroup),

the C₁-C₆₀ heterocyclic group may be a T2 group, a group in which atleast two T2 groups are condensed, or a group in which at least one T2group is condensed with at least one T1 group (for example, a pyrrolegroup, a thiophene group, a furan group, an indole group, a benzoindolegroup, a naphthoindole group, an isoindole group, a benzoisoindolegroup, a naphthoisoindole group, a benzosilole group, a benzothiophenegroup, a benzofuran group, a carbazole group, a dibenzosilole group, adibenzothiophene group, a dibenzofuran group, an indenocarbazole group,an indolocarbazole group, a benzofurocarbazole group, abenzothienocarbazole group, a benzosilolocarbazole group, abenzoindolocarbazole group, a benzocarbazole group, a benzonaphthofurangroup, a benzonapthothiophene group, a benzonaphthosilole group, abenzofurodibenzofuran group, a benzofurodibenzothiophene group, abenzothienodibenzothiophene group, a pyrazole group, an imidazole group,a triazole group, an oxazole group, an isoxazole group, an oxadiazolegroup, a thiazole group, an isothiazole group, a thiadiazole group, abenzopyrazole group, a benzimidazole group, a benzoxazole group, abenzoisoxazole group, a benzothiazole group, a benzoisothiazole group, apyridine group, a pyrimidine group, a pyrazine group, a pyridazinegroup, a triazine group, a quinoline group, an isoquinoline group, abenzoquinoline group, a benzoisoquinoline group, a quinoxaline group, abenzoquinoxaline group, a quinazoline group, a benzoquinazoline group, aphenanthroline group, a cinnoline group, a phthalazine group, anaphthyridine group, an imidazopyridine group, an imidazopyrimidinegroup, an imidazotriazine group, an imidazopyrazine group, animidazopyridazine group, an azacarbazole group, an azafluorene group, anazadibenzosilole group, an azadibenzothiophene group, an azadibenzofurangroup, and the like),

the π electron-rich C₃-C₆₀ cyclic group may be a T1 group, a condensedgroup in which at least two T1 groups are condensed, a T3 group, acondensed group in which at least two T3 groups are condensed, or acondensed group in which at least one T3 group is condensed with atleast one T1 group (for example, a C₃-C₆₀ carbocyclic group, a1H-pyrrole group, a silole group, a borole group, a 2H-pyrrole group, a3H-pyrrole group, a thiophene group, a furan group, an indole group, abenzoindole group, a naphthoindole group, an isoindole group, abenzoisoindole group, a naphthoisoindole group, a benzosilole group, abenzothiophene group, a benzofuran group, a carbazole group, adibenzosilole group, a dibenzothiophene group, a dibenzofuran group, anindenocarbazole group, an indolocarbazole group, a benzofurocarbazolegroup, a benzothienocarbazole group, a benzosilolocarbazole group, abenzoindolocarbazole group, a benzocarbazole group, a benzonaphthofurangroup, a benzonapthothiophene group, a benzonaphthosilole group, abenzofurodibenzofuran group, a benzofurodibenzothiophene group, abenzothienodibenzothiophene group, and the like), and

the π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group may bea T₄ group, a group in which at least two T4 groups are condensed, agroup in which at least one T4 group is condensed with at least one T1group, a group in which at least one T4 group is condensed with at leastone T3 group, or a group in which at least one T4 group, at least one T1group, and at least one T3 group are condensed (for example, a pyrazolegroup, an imidazole group, a triazole group, an oxazole group, anisoxazole group, an oxadiazole group, a thiazole group, an isothiazolegroup, a thiadiazole group, a benzopyrazole group, a benzimidazolegroup, a benzoxazole group, a benzoisoxazole group, a benzothiazolegroup, a benzoisothiazole group, a pyridine group, a pyrimidine group, apyrazine group, a pyridazine group, a triazine group, a quinoline group,an isoquinoline group, a benzoquinoline group, a benzoisoquinolinegroup, a quinoxaline group, a benzoquinoxaline group, a quinazolinegroup, a benzoquinazoline group, a phenanthroline group, a cinnolinegroup, a phthalazine group, a naphthyridine group, an imidazopyridinegroup, an imidazopyrimidine group, an imidazotriazine group, animidazopyrazine group, an imidazopyridazine group, an azacarbazolegroup, an azafluorene group, an azadibenzosilole group, anazadibenzothiophene group, an azadibenzofuran group, and the like),

wherein the T1 group may be a cyclopropane group, a cyclobutane group, acyclopentane group, a cyclohexane group, a cycloheptane group, acyclooctane group, a cyclobutene group, a cyclopentene group, acyclopentadiene group, a cyclohexene group, a cyclohexadiene group, acycloheptene group, an adamantane group, a norbornane (orbicyclo[2.2.1]heptane) group, a norbornene group, abicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, abicyclo[2.2.2]octane group, or a benzene group,

the T2 group may be a furan group, a thiophene group, a 1H-pyrrolegroup, a silole group, a borole group, a 2H-pyrrole group, a 3H-pyrrolegroup, an imidazole group, a pyrazole group, a triazole group, atetrazole group, an oxazole group, an isoxazole group, an oxadiazolegroup, a thiazole group, an isothiazole group, a thiadiazole group, anazasilole group, an azaborole group, a pyridine group, a pyrimidinegroup, a pyrazine group, a pyridazine group, a triazine group, atetrazine group, a pyrrolidine group, an imidazolidine group, adihydropyrrole group, a piperidine group, a tetrahydropyridine group, adihydropyridine group, a hexahydropyrimidine group, atetrahydropyrimidine group, a dihydropyrimidine group, a piperazinegroup, a tetrahydropyrazine group, a dihydropyrazine group, atetrahydropyridazine group, or a dihydropyridazine group,

the T3 group may be a furan group, a thiophene group, a 1H-pyrrolegroup, a silole group, or a borole group, and

the T4 group may be a 2H-pyrrole group, a 3H-pyrrole group, an imidazolegroup, a pyrazole group, a triazole group, a tetrazole group, an oxazolegroup, an isoxazole group, an oxadiazole group, a thiazole group, anisothiazole group, a thiadiazole group, an azasilole group, an azaborolegroup, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a triazine group, or a tetrazine group.

The terms “cyclic group”, “C₃-C₆₀ carbocyclic group”, “C₁-C₆₀heterocyclic group”, “π electron-rich C₃-C₆₀ cyclic group”, or “nelectron-deficient nitrogen-containing C₁-C₆₀ cyclic group” as usedherein may be a group condensed with any suitable cyclic group, amonovalent group, or a polyvalent group (e.g., a divalent group, atrivalent group, a tetravalent group, or the like), depending on thestructure of a formula to which the term is applied. For example, a“benzene group” may be a benzene ring, a phenyl group, a phenylenegroup, or the like, and this may be understood by one of ordinary skillin the art, depending on the structure of the formula including the“benzene group”.

Examples of the monovalent C₃-C₆₀ carbocyclic group and the monovalentC₁-C₆₀ heterocyclic group may include a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroarylgroup, a monovalent non-aromatic condensed polycyclic group, and amonovalent non-aromatic condensed heteropolycyclic group. Examples ofthe divalent C₃-C₆₀ carbocyclic group and the divalent C₁-C₆₀heterocyclic group may include a C₃-C₁₀ cycloalkylene group, a C₁-C₁₀heterocycloalkylene group, a C₃-C₁₀ cycloalkenylene group, a C₁-C₁₀heterocycloalkenylene group, a C₆-C₆₀ arylene group, a C₁-C₆₀heteroarylene group, a divalent non-aromatic condensed polycyclic group,and a divalent non-aromatic condensed heteropolycyclic group.

The term “C₁-C₆₀ alkyl group” as used herein may be a linear or branchedaliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms.Examples of the C₁-C₆₀ alkyl group may include a methyl group, an ethylgroup, an n-propyl group, an iso-propyl group, an n-butyl group, asec-butyl group, an isobutyl group, a tert-butyl group, an n-pentylgroup, a tert-pentyl group, a neopentyl group, an isopentyl group, asec-pentyl group, a 3-pentyl group, a sec-isopentyl group, an n-hexylgroup, an iso-hexyl group, a sec-hexyl group, a tert-hexyl group, ann-heptyl group, an iso-heptyl group, a sec-heptyl group, a tert-heptylgroup, an n-octyl group, an iso-octyl group, a sec-octyl group, atert-octyl group, an n-nonyl group, an iso-nonyl group, a sec-nonylgroup, a tert-nonyl group, an n-decyl group, an iso-decyl group, asec-decyl group, and a tert-decyl group. The term “C₁-C₆₀ alkylenegroup” as used herein may be a divalent group having a same structure asthe C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group” as used herein may be a monovalenthydrocarbon group having at least one carbon-carbon double bond in themiddle or at the terminus of the C₂-C₆₀ alkyl group. Examples thereofmay include an ethenyl group, a propenyl group, and a butenyl group. Theterm “C₂-C₆₀ alkenylene group” as used herein may be a divalent grouphaving a same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein may be a monovalenthydrocarbon group having at least one carbon-carbon triple bond in themiddle or at the terminus of the C₂-C₆₀ alkyl group. Examples thereofmay include an ethynyl group and a propynyl group. The term “C₂-C₆₀alkynylene group” as used herein may be a divalent group having a samestructure as the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group” as used herein may be a monovalent grouprepresented by —O(A₁₀₁) (wherein A₁₀₁ is a C₁-C₆₀ alkyl group). Examplesthereof may include a methoxy group, an ethoxy group, and anisopropyloxy group.

The term “C₃-C₁₀ cycloalkyl group” as used herein may be a monovalentsaturated hydrocarbon monocyclic group including 3 to 10 carbon atoms.Examples of the C₃-C₁₀ cycloalkyl group as used herein may include acyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, anorbornanyl (bicyclo[2.2.1]heptyl) group, a bicyclo[1.1.1]pentyl group,a bicyclo[2.1.1]hexyl group, or a bicyclo[2.2.2]octyl group. The term“C₃-C₁₀ cycloalkylene group” as used herein may be a divalent grouphaving a same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein may be amonovalent cyclic group including at least one heteroatom other thancarbon atoms as a ring-forming atom and having 1 to 10 carbon atoms.Examples thereof may include a 1,2,3,4-oxatriazolidinyl group, atetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term“C₁-C₁₀ heterocycloalkylene group” as used herein may be a divalentgroup having a same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein may be a monovalentcyclic group that has 3 to 10 carbon atoms and at least onecarbon-carbon double bond in its ring, and is not aromatic. Examplesthereof may include a cyclopentenyl group, a cyclohexenyl group, and acycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group” as usedherein may be a divalent group having a same structure as the C₃-C₁₀cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein may be amonovalent cyclic group including at least one heteroatom other thancarbon atoms as a ring-forming atom, 1 to 10 carbon atoms, and at leastone double bond in its ring. Examples of the C₁-C₁₀ heterocycloalkenylgroup may include a 4,5-dihydro-1,2,3,4-oxatriazolyl group, a2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term“C₁-C₁₀ heterocycloalkenylene group” as used herein may be a divalentgroup having a same structure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein may be a monovalent grouphaving a carbocyclic aromatic system having 6 to 60 carbon atoms. Theterm “C₆-C₆₀ arylene group” as used herein may be a divalent grouphaving a carbocyclic aromatic system having 6 to 60 carbon atoms.Examples of the C₆-C₆₀ aryl group may include a phenyl group, apentalenyl group, a naphthyl group, an azulenyl group, an indacenylgroup, an acenaphthyl group, a phenalenyl group, a phenanthrenyl group,an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenylgroup, a heptalenyl group, a naphthacenyl group, a picenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, and an ovalenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀arylene group each independently include two or more rings, therespective rings may be fused.

The term “C₁-C₆₀ heteroaryl group” as used herein may be a monovalentgroup having a heterocyclic aromatic system further including at leastone heteroatom other than carbon atoms as a ring-forming atom and 1 to60 carbon atoms. The term “C₁-C₆₀ heteroarylene group” as used hereinmay be a divalent group having a heterocyclic aromatic system furtherincluding at least one heteroatom other than carbon atoms as aring-forming atom and 1 to 60 carbon atoms. Examples of the C₁-C₆₀heteroaryl group may include a pyridinyl group, a pyrimidinyl group, apyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinylgroup, a benzoquinolinyl group, an isoquinolinyl group, abenzoisoquinolinyl group, a quinoxalinyl group, a benzoquinoxalinylgroup, a quinazolinyl group, a benzoquinazolinyl group, a cinnolinylgroup, a phenanthrolinyl group, a phthalazinyl group, and anaphthyridinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀heteroarylene group each independently include two or more rings, therespective rings may be fused.

The term “monovalent non-aromatic condensed polycyclic group” as usedherein may be a monovalent group that has two or more condensed ringsand only carbon atoms (e.g., 8 to 60 carbon atoms) as ring formingatoms, wherein the molecular structure when considered as a whole isnon-aromatic. Examples of the monovalent non-aromatic condensedpolycyclic group may include an indenyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, an indenophenanthrenylgroup, and an indenoanthracenyl group. The term “divalent non-aromaticcondensed polycyclic group” as used herein may be a divalent grouphaving substantially a same structure as the monovalent non-aromaticcondensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” asused herein may be a monovalent group that has two or more condensedrings and at least one heteroatom other than carbon atoms (e.g., 1 to 60carbon atoms), as a ring-forming atom, wherein the molecular structurewhen considered as a whole is non-aromatic. Examples of the monovalentnon-aromatic condensed heteropolycyclic group may include a pyrrolylgroup, a thiophenyl group, a furanyl group, an indolyl group, abenzoindolyl group, a naphthoindolyl group, an isoindolyl group, abenzoisoindolyl group, a naphthoisoindolyl group, a benzosilolyl group,a benzothiophenyl group, a benzofuranyl group, a carbazolyl group, adibenzosilolyl group, a dibenzothiophenyl group, a dibenzofuranyl group,an azacarbazolyl group, an azafluorenyl group, an azadibenzosilolylgroup, an azadibenzothiophenyl group, an azadibenzofuranyl group, apyrazolyl group, an imidazolyl group, a triazolyl group, a tetrazolylgroup, an oxazolyl group, an isoxazolyl group, a thiazolyl group, anisothiazolyl group, an oxadiazolyl group, a thiadiazolyl group, abenzopyrazolyl group, a benzimidazolyl group, a benzoxazolyl group, abenzothiazolyl group, a benzooxadiazolyl group, a benzothiadiazolylgroup, an imidazopyridinyl group, an imidazopyrimidinyl group, animidazotriazinyl group, an imidazopyrazinyl group, an imidazopyridazinylgroup, an indenocarbazolyl group, an indolocarbazolyl group, abenzofurocarbazolyl group, a benzothienocarbazolyl group, abenzosilolocarbazolyl group, a benzoindolocarbazolyl group, abenzocarbazolyl group, a benzonaphthofuranyl group, abenzonaphthothiophenyl group, a benzonaphthosilolyl group, abenzofurodibenzofuranyl group, a benzofurodibenzothiophenyl group, and abenzothienodibenzothiophenyl group. The term “divalent non-aromaticcondensed heteropolycyclic group” as used herein may be a divalent grouphaving substantially a same structure as the monovalent non-aromaticcondensed heteropolycyclic group.

The term “C₆-C₆₀ aryloxy group” as used herein indicates —OA₁₀₂ (whereinA₁₀₂ is a C₆-C₆₀ aryl group), and a C₆-C₆₀ arylthio group as used hereinindicates —SA₁₀₃ (wherein A₁₀₃ is a C₆-C₆₀ aryl group).

The term “C₇-C₆₀ aryl alkyl group” used herein refers to -A₁₀₄A₁₀₅(where A₁₀₄ may be a C₁-C₅₄ alkylene group, and A₁₀₅ may be a C₆-C₅₉aryl group), and the term “C₂-C₆₀ heteroaryl alkyl group” used hereinrefers to -A₁₀₆A₁₀₇ (where A₁₀₆ may be a C₁-C₅₉ alkylene group, and A₁₀₇may be a C₁-C₅₉ heteroaryl group).

The term “R_(10a)” as used herein may be:

deuterium (-D), —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or anitro group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, ora C₁-C₆₀ alkoxy group, each unsubstituted or substituted with deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, aC₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₇-C₆₀ aryl alkyl group, a C₂-C₆₀heteroaryl alkyl group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂),—C(═O)(Q₁₁), —S(═O)₂(Q₁₁), —P(═O)(Q₁₁)(Q₁₂), or any combination thereof;

a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ aryl alkyl group, or aC₂-C₆₀ heteroaryl alkyl group, each unsubstituted or substituted withdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₇-C₆₀ aryl alkyl group, a C₂-C₆₀ heteroaryl alkyl group,—Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁),—S(═O)₂(Q₂₁), —P(═O)(Q₂₁)(Q₂₂), or any combination thereof, or

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), or —P(═O)(Q₃₁)(Q₃₂).

Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃ and Q₃₁ to Q₃₃ may each independentlybe: hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a cyanogroup; a nitro group; a C₁-C₆₀ alkyl group; a C₂-C₆₀ alkenyl group; aC₂-C₆₀ alkynyl group; a C₁-C₆₀ alkoxy group; a C₃-C₆₀ carbocyclic groupor a C₁-C₆₀ heterocyclic group, each unsubstituted or substituted withdeuterium, —F, a cyano group, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxygroup, a phenyl group, a biphenyl group, or any combination thereof, aC₇-C₆₀ aryl alkyl group; or a C₂-C₆₀ heteroaryl alkyl group.

The term “heteroatom” as used herein may be any atom other than a carbonatom or a hydrogen atom. Examples of the heteroatom may include O, S, N,P, Si, B, Ge, Se, or any combination thereof.

The term “third-row transition metal” as used herein may include hafnium(Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium(Ir), platinum (Pt), and gold (Au).

The term “Ph” as used herein represents a phenyl group, the term “Me” asused herein represents a methyl group, the term “Et” as used hereinrepresents an ethyl group, the terms “tert-Bu” or “Bu^(t)” as usedherein each represent a tert-butyl group, and the term “OMe” as usedherein represents a methoxy group.

The term “biphenyl group” as used herein may be a phenyl groupsubstituted with a phenyl group. For example, the “biphenyl group” maybe a substituted phenyl group having a C₆-C₆₀ aryl group as asubstituent.

The term “terphenyl group” as used herein may be a phenyl groupsubstituted with a biphenyl group. For example, the “terphenyl group”may be “a substituted phenyl group” having a “C₆-C₆₀ aryl groupsubstituted with a C₆-C₆₀ aryl group” as a substituent.

The symbols *, *′, *″, and *′″ as used herein, unless defined otherwise,refer to a binding site to an adjacent atom in a corresponding formulaor moiety.

Hereinafter, compounds and a light-emitting device according toembodiments will be described in more detail with reference to SynthesisExamples and Examples. The wording “B was used instead of A” used indescribing Synthesis Examples means that an amount of B used wasidentical to an amount of A used in terms of molar equivalents.

EXAMPLES Synthesis Example 1: Synthesis of Compound 1

(1) Synthesis of Intermediate [1-A]

2-bromo-1,4-difluorobenzene (2.0 eq.), imidazole (1.0 eq.), and K₃PO₄(2.0 eq.) were added to a reaction vessel, followed by suspension indimethyl formamide (DMF, 0.25 molar (M)). The reaction mixture washeated to a temperature of 160° C. and stirred for 12 hours. Once thereaction was complete, the mixture was cooled to room temperature, andan extraction process was performed thereon by using distilled water andethyl acetate. The extracted organic layer was washed using saturatedNaCl aqueous solution and dried using magnesium sulfate. The residuefrom which the solvent was removed was separated by using columnchromatography to thereby obtain Intermediate [1-A] (yield: 73%).

(2) Synthesis of Intermediate [1-B]

Intermediate [1-A] (1.0 eq.), carbazole (1.5 eq.), and K₃PO₄ (2.0 eq.)were added to a reaction vessel, followed by suspension in DMF (0.25 M).The reaction mixture was heated to a temperature of 160° C. and stirredfor 12 hours. Once the reaction was complete, the mixture was cooled toroom temperature, and an extraction process was performed thereon byusing distilled water and ethyl acetate. The extracted organic layer waswashed using saturated NaCl aqueous solution and dried using magnesiumsulfate. The residue from which the solvent was removed was separated byusing column chromatography to thereby obtain Intermediate [1-B](yield:80%).

(3) Synthesis of Intermediate [1-C]

3-fluoroacetophenone (2.0 eq.), Mg (2.0 eq.), and iodine (0.01 eq.) wereadded to a reaction vessel, followed by suspension in anhydroustetrahydrofuran (THF, 0.5 M) in argon atmosphere. The reaction mixturewas heated to a temperature of 60° C. and stirred for 2 hours.Intermediate [1-B] (1.0 eq.) was added dropwise slowed to the stirredmixture. The reaction mixture was stirred at a temperature of 60° C. for12 hours. Once the reaction was complete, the reaction mixture wascooled to room temperature, and an ammonium chloride solution was addedthereto, followed by extraction using ethyl acetate. The extractedorganic layer was dried using magnesium sulfate. The residue from whichthe solvent was removed was separated by using column chromatography tothereby obtain Intermediate [1-C] (yield: 72%).

(4) Synthesis of Intermediate [1-D]

Intermediate [1-C] (1.0 eq.) was added to a reaction vessel, followed bysuspension in methylene chloride (0.5 M). At room temperature, triflicacid (1.5 eq) was slowly added thereto dropwise to the reaction mixture.The reaction mixture was stirred at a temperature of 25° C. for 12hours. Once the reaction was complete, neutralization using NaOH andammonium chloride was carried out, followed by extraction usingmethylene chloride. The extracted organic layer was washed usingsaturated NaCl aqueous solution and dried using magnesium sulfate. Theresidue from which the solvent was removed was separated by using columnchromatography to thereby obtain Intermediate [1-D] (yield: 85%).

(5) Synthesis of Intermediate [1-E]

Intermediate [1-E] was synthesized in the same manner as in Synthesis ofIntermediate [1-A], except that Intermediate [1-D] was used instead of2-bromo-1,4-difluorobenzene (yield: 82%).

(6) Synthesis of Intermediate [1-F]

Intermediate [1-E] (1.0 eq.) and iodomethane (10.0 eq.) were added to areaction vessel, followed by suspension in toluene (0.1 M). The reactionmixture was heated to a temperature of 110° C. and stirred for 12 hours.Once the reaction was complete, the mixture was cooled to roomtemperature, and an extraction process was performed thereon by usingdistilled water and ethyl acetate. The extracted organic layer was driedusing magnesium sulfate, and the solvent was removed therefrom tothereby obtain Intermediate [1-F] (yield: 90%).

(7) Synthesis of Intermediate [1-G]

Intermediate [1-F] (1.0 eq.) was added to a reaction vessel, followed bysuspension onto a mixed solution of methanol and distilled water at aratio of 2:1. The reaction mixture was sufficiently dissolved, andammonium hexafluorophosphate (2.2 eq.) was slowly added thereto,followed by stirring the reaction solution at room temperature for 12hours. Once the reaction was complete, the thus produced solid wasfiltered and washed using diethyl ether. The washed solid was dried toobtain Intermediate [1-G] (yield: 93%).

(8) Synthesis of Compound 1

Intermediate [1-G] (1.0 eq.), dichloro(1,5-cyclooctadiene)platinum (1.1eq.), and sodium acetate (3.0 eq.) were suspended in 1,4-dioxane (0.1M). The reaction mixture was heated to a temperature of 120° C. andstirred for 72 hours. Once the reaction was complete, the reactionmixture was cooled to room temperature, and an extraction process wasperformed thereon by using distilled water and ethyl acetate. Theextracted organic layer was washed using saturated NaCl aqueous solutionand dried using magnesium sulfate. The residue from which the solventwas removed was separated by using column chromatography to therebyobtain Compound 1 (yield: 32%).

Synthesis Example 2: Synthesis of Compound 11

(1) Synthesis of Intermediate [11-B]

Intermediate [11-B] was synthesized in the same manner as in Synthesisof Intermediate [1-B], except that 3-tert-Butyl-9H-carbazole was usedinstead of carbazole (yield: 78%).

(2) Synthesis of Intermediate [11-C]

Intermediate [11-C] was synthesized in the same manner as in Synthesisof Intermediate [1-C], except that Intermediate [11-B] was used insteadof Intermediate [1-B](yield: 76%).

(3) Synthesis of Intermediate [11-D]

Intermediate [11-D] was synthesized in the same manner as in Synthesisof Intermediate [1-D], except that Intermediate [11-C] was used insteadof Intermediate [1-C](yield: 80%).

(4) Synthesis of Intermediate [11-E]

Intermediate [11-E] was synthesized in the same manner as in Synthesisof Intermediate [1-E], except that Intermediate [11-D] was used insteadof Intermediate [1-D](yield: 73%).

(5) Synthesis of Intermediate [11-F]

Intermediate [11-F] was synthesized in the same manner as in Synthesisof Intermediate [1-F], except that Intermediate [11-E] was used insteadof Intermediate [1-E](yield: 85%).

(6) Synthesis of Intermediate [11-G]

Intermediate [11-G] was synthesized in the same manner as in Synthesisof Intermediate [1-G], except that Intermediate [11-F] was used insteadof Intermediate [1-F](yield: 92%).

(7) Synthesis of Compound 11

Compound 11 was synthesized in the same manner as in Synthesis ofCompound 1, except that Intermediate [11-G] was used instead ofIntermediate [1-G] (yield: 36%).

Synthesis Example 3: Synthesis of Compound 71

(1) Synthesis of Intermediate [71-A]

1-bromo-4-fluoro-2-nitrobenzene (1.0 eq.), imidazole (1.2 eq.), andK₃PO₄ (2.0 eq.) were added to a reaction vessel, followed by suspensionin DMF (0.25 M). The reaction mixture was heated to a temperature of160° C. and stirred for 24 hours. Once the reaction was complete, themixture was cooled to room temperature, and an extraction process wasperformed thereon by using distilled water and ethyl acetate. Theextracted organic layer was washed using saturated NaCl aqueous solutionand dried using magnesium sulfate. The residue from which the solventwas removed was separated by using column chromatography to therebyobtain Intermediate [71-A] (yield: 92%).

(2) Synthesis of Intermediate [71-B]

Intermediate [71-A] (1.0 eq.), carbazole (1.2 eq.), K₂CO₃ (2.0 eq.), CuI(0.1 eq.), and 1,10-phenanthroline (0.1 eq.) were added to a reactionvessel, followed by suspension in DMF (0.25 M). The reaction mixture washeated to a temperature of 160° C. and stirred for 24 hours. Once thereaction was complete, the mixture was cooled to room temperature, andan extraction process was performed thereon by using distilled water andethyl acetate. The extracted organic layer was washed using saturatedNaCl aqueous solution and dried using magnesium sulfate. The residuefrom which the solvent was removed was separated by using columnchromatography to thereby obtain Intermediate [71-B] (yield: 73%).

(3) Synthesis of Intermediate [71-C]

Intermediate [71-B] (1.0 eq.) and triethylphosphite (6.0 eq.) were addedto a reaction vessel, followed by suspension. The reaction mixture washeated to a temperature of 120° C. and stirred for 12 hours. Once thereaction was complete, the mixture was cooled to room temperature, andthe solvent was removed therefrom under reduced pressure. The residuewas extracted using distilled water and ethyl acetate. The extractedorganic layer was washed using saturated NaCl aqueous solution and driedusing magnesium sulfate. The residue from which the solvent was removedwas separated by using column chromatography to thereby obtainIntermediate [71-C] (yield: 60%).

(4) Synthesis of Intermediate [71-D]

Intermediate [71-C] (1.0 eq.), 1,3-dibromobenzene (2.0 eq.), Pd₂(dba)₃(0.05 eq.), Sphos (0.075 eq.), and sodium tert-butoxide (2.0 eq.) wereadded to a reaction vessel, followed by suspension in toluene (0.1 M).The reaction mixture was heated to a temperature of 110° C. and stirredfor 4 hours. Once the reaction was complete, the mixture was cooled toroom temperature, and an extraction process was performed thereon byusing distilled water and ethyl acetate. The extracted organic layer waswashed using saturated NaCl aqueous solution and dried using magnesiumsulfate. The residue from which the solvent was removed was separated byusing column chromatography to thereby obtain Intermediate [71-D](yield: 65%).

(5) Synthesis of Intermediate [71-E]

Intermediate [71-D] (1.0 eq.), imidazole (1.2 eq.), K₂CO₃ (2.0 eq.), CuI(0.1 eq.), and 1,10-phenanthroline (0.1 eq.) were added to a reactionvessel, followed by suspension in DMF (0.25 M). The reaction mixture washeated to a temperature of 160° C. and stirred for 24 hours. Once thereaction was complete, the mixture was cooled to room temperature, andan extraction process was performed thereon by using distilled water andethyl acetate. The extracted organic layer was washed using saturatedNaCl aqueous solution and dried using magnesium sulfate. The residuefrom which the solvent was removed was separated by using columnchromatography to thereby obtain Intermediate [71-E] (yield: 76%).

(6) Synthesis of Intermediate [71-F]

Intermediate [71-F] was synthesized in the same manner as in Synthesisof Intermediate [1-F], except that Intermediate [71-E] was used insteadof Intermediate [1-E](yield: 93%).

(7) Synthesis of Intermediate [71-G]

Intermediate [71-G] was synthesized in the same manner as in Synthesisof Intermediate [1-G], except that Intermediate [71-F] was used insteadof Intermediate [1-F](yield: 90%).

8) Synthesis of Compound 71

Compound 71 was synthesized in the same manner as in Synthesis ofCompound 1, except that Intermediate [71-G] was used instead ofIntermediate [1-G] (yield: 34%).

The ¹H nuclear magnetic resonance (NMR) and mass spectroscopy/fast atombombardment (MS/FAB) results are shown in Table 1.

TABLE 1 MS/FAB Compound ¹H NMR (CDCl₃, 400 MHz) found Calc. 1 2.28(s,3H), 3.72(s, 6H), 7.07(t, 1H), 7.16-7.18(m, 698.18 698.69 2H), 7.27(m,2H), 7.34-7.35(m, 2H), 7.44-7.45(m, 3H), 7.5l(d, 1H), 7.65(d, 1H),7.72(d, 1H), 7.93(d, 1H), 8.09(d, 1H), 8.56(d, 1H) 11 1.42(s, 9H),2.27(s, 3H), 3.71(s, 6H), 7.08(t, 1H), 754.24 754.80 7.11(d, 1H),7.18(d, 1H), 7.28(d, 2H), 7.34(t, 1H), 7.44- 7.45(m, 3H), 7.5l(d, 1H),7.66(d, 1H), 7.72(d, 1H), 7.86 (d, 1H), 8.09(d, 1H), 8.96(s, 1H) 713.72(s, 6H), 7.16-7.19(m, 2H), 7.24-7.27(m, 4H), 685.16 685.657.32-7.35(m, 3H), 7.41(d, 1H), 7.44(d, 2H), 7.69(d, 1H), 7.86(d, 1H),7.94(d, 1H), 8.55(d, 1H)

Methods of synthesizing compounds other than the compounds synthesizedin Synthesis Examples 1 to 3 may be easily understood to those skilledin the art by referring to the synthesis pathways and raw materialsdescribed above.

Example 1-1

As an anode, a 15 Ohms per square centimeter (Ω/cm²) (1,200 Å) ITO glasssubstrate (available from Corning Co., Ltd) was cut to a size of 50millimeters (mm)×50 mm×0.7 mm, sonicated in isopropyl alcohol and purewater for 5 minutes in each solvent, cleaned with ultraviolet rays for30 minutes, and with ozone, and was mounted on a vacuum depositionapparatus.

2-TNATA was vacuum-deposited on the anode to form a hole injection layerhaving a thickness of 600 Å, and4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (hereinafter, referred as“NPB”) was vacuum-deposited on the hole injection layer to form a holetransport layer having a thickness of 300 Å.

Compound 1 (the first compound), Compound ETH68 (the second compound),and Compound HTH29 (the third compound) were vacuum-deposited on thehole transport layer to form an emission layer having a thickness of 400Å. Here, the content of Compound 1 was 10 wt %, based on 100 wt % of thetotal weight of the emission layer, and the weight ratio of CompoundETH68 to Compound HTH29 was 3:7.

Compound ETH2 was deposited on the emission layer to form a holeblocking layer having a thickness of 50 Å, Alq₃ was deposited on thehole blocking layer to form an electron transport layer having athickness of 300 Å, LiF was vacuum-deposited on the electron transportlayer to form an electron injection layer having a thickness of 10 Å,and A1 was vacuum-deposited on the electron injection layer to form acathode having a thickness of 3,000 Å, thereby completing themanufacture of an organic light-emitting device.

Examples 1-2 and 1-3 and Comparative Examples 1-1 to 1-3

Organic light-emitting devices were manufactured in the same manner asin Example 1-1, except that the first compound, the second compound, andthe third compound as shown in Table 2 were used in the formation of theemission layer.

Evaluation Example 1

The driving voltage (V), luminescence efficiency (cd/A), maximumemission wavelength (nm), and lifespan (LT₉₅) of the organiclight-emitting devices of Examples 1-1 to 1-3 and Comparative Examples1-1 to 1-3 at 1,000 cd/m² were measured by using Keithley source-measureunit (SMIU) 236 and a luminance meter PR650. The results thereof areshown in Table 2. In Table 2, the lifespan (LT₉₅) indicates a time(hour) for the luminance of each light-emitting device to decline to 95%of its initial luminance.

TABLE 2 Dopant Host Driving Luminescence Maximum Lifespan First SecondThird Luminance voltage efficiency emission (LT₉₅) compound compoundcompound (cd/m²) (V) (cd/A) wavelength (nm) (hours) Example 1-1 1 ETH68HTH29 1000 4.3 20.1 457 87.0 Example 1-2 11 ETH68 HTH29 1000 4.2 20.8458 86.9 Example 1-3 71 ETH68 HTH29 1000 4.2 22.1 464 90.2 Comparative AETH68 HTH29 1000 4.3 17.8 465 84.1 Example 1-1 Comparative B ETH68 HTH291000 4.7 15.1 464 57.9 Example 1-2 Comparative C ETH68 HTH29 1000 5.112.2 474 13.8 Example 1-3

Referring to the results of Table 2, the organic light-emitting devicesof Examples 1-1 to 1-3 were found to have a low driving voltage,excellent luminescence efficiency, and lifespan characteristics and emitdark blue light.

Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3

Organic light-emitting devices were manufactured in the same manner asin Example 1-1, except that the first compound, the second compound, andthe third compound as shown in Table 3 were used to form the emissionlayer, a fourth compound was additionally used, a content of the firstcompound was 10 wt % based on the total content of (100 wt %) of theemission layer, a content of the fourth compound was 0.5 wt % based onthe total content of (100 wt % o) of the emission layer, and the weightratio of the second compound to third compound was adjusted to 3:7.

Evaluation Example 2

The driving voltage (V), luminescence efficiency (cd/A), maximumemission wavelength (nm), and lifespan (LT₉₅) of the organiclight-emitting devices of Examples 2-1 to 2-3 and Comparative Examples2-1 to 2-3 at 1,000 cd/m² were measured by using Keithley SMU 236 and aluminance meter PR650. The results thereof are shown in Table 3. InTable 3, the lifespan (LT₉₅) indicates a time (hour) for the luminanceof each light-emitting device to decline to 95% of its initialluminance.

TABLE 3 Ancillary dopant Host Dopant Driving Luminescence Lifespan FirstSecond Third Fourth Luminance voltage efficiency Emission (LT₉₅)compound compound compound compound (cd/m²) (V) (cd/A) wavelength (nm)(hours) Example 2-1 1 ETH68 HTH29 DFD2 1000 4.4 18.9 461 56.3 Example2-2 11 ETH68 HTH29 DFD2 1000 4.4 18.1 461 54.9 Example 2-3 71 ETH68HTH29 DFD2 1000 4.3 19.3 461 58.1 Comparative A ETH68 HTH29 DFD2 10004.5 16.7 461 49.9 Example 2-1 Comparative B ETH68 HTH29 DFD2 1000 4.713.5 462 34.1 Example 2-2 Comparative C ETH68 HTH29 DFD2 1000 5.0 10.5.472 10.1 Example 2-3

Referring to the results of Table 3, the organic light-emitting devicesof Examples 2-1 to 2-3 were found to have a low driving voltage,excellent luminescence efficiency, and lifespan characteristics and emitdark blue light.

Embodiments have been disclosed herein, and although terms are employed,they are used and are to be interpreted in a generic and descriptivesense only and not for purpose of limitation. In some instances, aswould be apparent by one of ordinary skill in the art, features,characteristics, and/or elements described in connection with anembodiment may be used singly or in combination with features,characteristics, and/or elements described in connection with otherembodiments unless otherwise specifically indicated. Accordingly, itwill be understood by those of ordinary skill in the art that variouschanges in form and details may be made without departing from thespirit and scope of the disclosure as set forth in the claims.

What is claimed is:
 1. A light-emitting device comprising: a firstelectrode; a second electrode facing the first electrode; an interlayerdisposed between the first electrode and the second electrode andcomprising an emission layer; and an organometallic compound representedby Formula 1:

wherein in Formula 1, M is platinum (Pt), palladium (Pd), nickel (Ni),copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir),ruthenium (Ru), osmium (Os), titanium (Ti), zirconium (Zr), hafnium(Hf), europium (Eu), terbium (Tb), or thulium (Tm), X₁ to X₄ are eachindependently carbon (C) or nitrogen (N), Y₁ is N, A₁ to A₄ are eachindependently a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group,CY₁ is a C₁-C₆₀ heterocyclic group, T₁ is N, B, P, C(Z₁₁), Si(Z₁₁), orGe(Z₁₁), T₂ to T₄ are each independently a single bond, a double bond,*—N(Z₂₁)—*′, *—B(Z₂₁)—*′, *—P(Z₂₁)—*′, *—C(Z₂₁)(Z₂₂)—*′,*—Si(Z₂₁)(Z₂₂)—*′, *—Ge(Z₂₁)(Z₂₂)—*′, *—S—*′, *—Se—*′, *—O—*,*—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(Z₂₁)=*′, *═C(Z₂₁)—*′,*—C(Z₂₁)═C(Z₂₂)—*′, *—C(═S)—*′, or *—C≡C—*′, and * and *′ each indicatea binding site to an adjacent atom, a2 to a4 are each independently aninteger from 0 to 3, R₁ to R₅, Z₁₁, Z₂₁, and Z₂₂ are each independentlyhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, a C₁-C₆₀ alkyl group unsubstituted or substituted with atleast one R_(10a), a C₂-C₆₀ alkenyl group unsubstituted or substitutedwith at least one R_(10a), a C₂-C₆₀ alkynyl group unsubstituted orsubstituted with at least one R_(10a), a C₁-C₆₀ alkoxy groupunsubstituted or substituted with at least one R_(10a), a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least oneR_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), a C₆-C₆₀ aryloxy group unsubstituted orsubstituted with at least one R_(10a), a C₆-C₆₀ arylthio groupunsubstituted or substituted with at least one R_(10a), —Si(Q₁)(Q₂)(Q₃),—N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂), b1to b5 are each independently an integer from 0 to 10, two R₁(s) of atleast two R₁(s) when b1 is 2 or greater are optionally bound to eachother to form a C₃-C₆₀ carbocyclic group unsubstituted or substitutedwith at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstitutedor substituted with at least one R_(10a), two R₂(s) of at least twoR₂(s) when b2 is 2 or greater are optionally bound to each other to forma C₃-C₆₀ carbocyclic group unsubstituted or substituted with at leastone R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substitutedwith at least one R_(10a), two R₃(s) of at least two R₃(s) when b3 is 2or greater are optionally bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a), two R₄(s) of at least two R₄(s) when b4 is 2 orgreater are optionally bound to each other to form a C₃-C₆₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), two R₅(s) of at least two R₅(s) when b5 is 2 or greater areoptionally bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), and R_(10a) is: deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, or a nitro group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group, eachunsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, a C₃-C₆₀ carbocyclicgroup, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂),—C(═O)(Q₁₁), —S(═O)₂(Q₁₁), —P(═O)(Q₁₁)(Q₁₂), or a combination thereof; aC₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxygroup, or a C₆-C₆₀ arylthio group, each unsubstituted or substitutedwith deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, aC₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthiogroup, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁),—S(═O)₂(Q₂₁), —P(═O)(Q₂₁)(Q₂₂), or a combination thereof; or—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), or —P(═O)(Q₃₁)(Q₃₂), wherein Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ toQ₂₃, and Q₃₁ to Q₃₃ are each independently: hydrogen; deuterium; —F;—Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; a C₁-C₆₀alkyl group; a C₂-C₆₀ alkenyl group; a C₂-C₆₀ alkynyl group; a C₁-C₆₀alkoxy group; or a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclicgroup, each unsubstituted or substituted with deuterium, —F, a cyanogroup, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, abiphenyl group, or a combination thereof, and * and *′ each indicate abinding site to an adjacent atom.
 2. The light-emitting device of claim1, wherein the interlayer comprises: a first compound that is theorganometallic compound represented by Formula 1; and a second compoundcomprising at least one π electron-deficient nitrogen-containing C₁-C₆₀cyclic group, a third compound comprising a group represented by Formula3, a fourth compound capable of emitting delayed fluorescence, or acombination thereof, and the first compound, the second compound, thethird compound, and the fourth compound are different from one another:

wherein in Formula 3, ring CY₇₁ and ring CY72 are each independently a πelectron-rich C₃-C₆₀ cyclic group or a pyridine group, X₇₁ is a singlebond or a linking group comprising O, S, N, B, C, Si, or a combinationthereof, * indicates a binding site to an adjacent atom in the thirdcompound, and the following compounds are excluded from the thirdcompound:


3. The light-emitting device of claim 2, wherein the emission layercomprises: the first compound; and the second compound, the thirdcompound, the fourth compound, or a combination thereof, and theemission layer emits phosphorescence or fluorescence emitted from thefirst compound.
 4. The light-emitting device of claim 2, wherein thesecond compound comprises a pyridine group, a pyrimidine group, apyrazine group, a pyridazine group, a triazine group, or a combinationthereof.
 5. The light-emitting device of claim 2, wherein the fourthcompound is a compound comprising at least one cyclic group comprisingboron (B) and nitrogen (N) as ring-forming atoms.
 6. The light-emittingdevice of claim 2, wherein the second compound comprises a compoundrepresented by Formula 2:

wherein in Formula 2, L₆₁ to L₆₃ are each independently a single bond, aC₃-C₆₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a), or a C₁-C₆₀ heterocyclic group unsubstituted or substitutedwith at least one R_(10a), b61 to b63 are each independently an integerfrom 1 to 5, X₆₄ is N or C(R₆₄), X₆₅ is N or C(R₆₅), X₆₆ is N or C(R₆₆),at least one of X₆₄ to X₆₆ is N, R₆₁ to R₆₆ are each independentlyhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, a C₁-C₆₀ alkyl group unsubstituted or substituted with atleast one R_(10a), a C₂-C₆₀ alkenyl group unsubstituted or substitutedwith at least one R_(10a), a C₂-C₆₀ alkynyl group unsubstituted orsubstituted with at least one R_(10a), a C₁-C₆₀ alkoxy groupunsubstituted or substituted with at least one R_(10a), a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least oneR_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), a C₆-C₆₀ aryloxy group unsubstituted orsubstituted with at least one R_(10a), a C₆-C₆₀ arylthio groupunsubstituted or substituted with at least one R_(10a), —C(Q₁)(Q₂)(Q₃),—Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), or—P(═O)(Q₁)(Q₂), and R_(10a) and Q₁ to Q₃ are respectively the same asdescribed in connection with R_(10a) and Q₁ to Q₃ in Formula
 1. 7. Thelight-emitting device of claim 2, wherein at least one of Conditions 1to 4 is satisfied: [Condition 1] LUMO energy level in electron volts(eV) of the third compound >LUMO energy level in electron volts (eV) ofthe first compound [Condition 2] LUMO energy level in electron volts(eV) of the first compound >LUMO energy level in electron volts (eV) ofthe second compound [Condition 3] HOMO energy level in electron volts(eV) of the first compound >HOMO energy level in electron volts (eV) ofthe third compound [Condition 4] HOMO energy level in electron volts(eV) of the third compound >HOMO energy level in electron volts (eV) ofthe second compound.
 8. An electronic apparatus comprising: thelight-emitting device of claim 1; and a thin-film transistor, whereinthe thin-film transistor comprises a source electrode and a drainelectrode, and the first electrode of the light-emitting device iselectrically connected to at least one of the source electrode and thedrain electrode of the thin-film transistor.
 9. The electronic apparatusof claim 8, further comprising a color filter, a color-conversion layer,a touchscreen layer, a polarization layer, or a combination thereof. 10.An organometallic compound represented by Formula 1:

wherein in Formula 1, M is platinum (Pt), palladium (Pd), nickel (Ni),copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir),ruthenium (Ru), osmium (Os), titanium (Ti), zirconium (Zr), hafnium(Hf), europium (Eu), terbium (Tb), or thulium (Tm), X₁ to X₄ are eachindependently carbon (C) or nitrogen (N), Y₁ is N, A₁ to A₄ are eachindependently a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group,CY₁ is a C₁-C₆₀ heterocyclic group, T₁ is N, B, P, C(Z₁₁), Si(Z₁₁), orGe(Z₁₁), T₂ to T₄ are each independently a single bond, a double bond,*—N(Z₂₁)—*′, *—B(Z₂₁)—*′, *—P(Z₂₁)—*′, *—C(Z₂₁)(Z₂₂)—*′,*—Si(Z₂₁)(Z₂₂)—*′, *—Ge(Z₂₁)(Z₂₂)—*′, *—S—*′, *—Se—*′, *—O—*,*—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(Z₂₁)=*′, *═C(Z₂₁)—*′,*—C(Z₂₁)═C(Z₂₂)—*′, *—C(═S)—*′, or *—C≡C—*′, and * and *′ each indicatea binding site to an adjacent atom, a2 to a4 are each independently aninteger from 0 to 3, R₁ to R₅, Z₁₁, Z₂₁, and Z₂₂ are each independentlyhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, a C₁-C₆₀ alkyl group unsubstituted or substituted with atleast one R_(10a), a C₂-C₆₀ alkenyl group unsubstituted or substitutedwith at least one R_(10a), a C₂-C₆₀ alkynyl group unsubstituted orsubstituted with at least one R_(10a), a C₁-C₆₀ alkoxy groupunsubstituted or substituted with at least one R_(10a), a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least oneR_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), a C₆-C₆₀ aryloxy group unsubstituted orsubstituted with at least one R_(10a), a C₆-C₆₀ arylthio groupunsubstituted or substituted with at least one R_(10a), —Si(Q₁)(Q₂)(Q₃),—N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂), b1to b5 are each independently an integer from 0 to 10, two R₁(s) of atleast two R₁(s) when b1 is 2 or greater are optionally bound to eachother to form a C₃-C₆₀ carbocyclic group unsubstituted or substitutedwith at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstitutedor substituted with at least one R_(10a), two R₂(s) of at least twoR₂(s) when b2 is 2 or greater are optionally bound to each other to forma C₃-C₆₀ carbocyclic group unsubstituted or substituted with at leastone R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substitutedwith at least one R_(10a), two R₃(s) of at least two R₃(s) when b3 is 2or greater are optionally bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a), two R₄(s) of at least two R₄(s) when b4 is 2 orgreater are optionally bound to each other to form a C₃-C₆₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), two R₅(s) of at least two R₅(s) when b5 is 2 or greater areoptionally bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), and R_(10a) is: deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, or a nitro group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group, eachunsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, a C₃-C₆₀ carbocyclicgroup, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂),—C(═O)(Q₁₁), —S(═O)₂(Q₁₁), —P(═O)(Q₁₁)(Q₁₂), or a combination thereof; aC₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxygroup, or a C₆-C₆₀ arylthio group, each unsubstituted or substitutedwith deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, aC₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthiogroup, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁),—S(═O)₂(Q₂₁), —P(═O)(Q₂₁)(Q₂₂), or a combination thereof; or—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), or —P(═O)(Q₃₁)(Q₃₂), wherein Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ toQ₂₃, and Q₃₁ to Q₃₃ are each independently: hydrogen; deuterium; —F;—Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; a C₁-C₆₀alkyl group; a C₂-C₆₀ alkenyl group; a C₂-C₆₀ alkynyl group; a C₁-C₆₀alkoxy group; or a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclicgroup, each unsubstituted or substituted with deuterium, —F, a cyanogroup, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, abiphenyl group, or a combination thereof, and * and *′ each indicate abinding site to an adjacent atom.
 11. The organometallic compound ofclaim 10, wherein a bond between X₁ and M is a covalent bond, a bondbetween X₂ and M is a covalent bond, a bond between X₃ and M is acoordinate bond, and a bond between X₄ and M is a covalent bond or acoordinate bond.
 12. The organometallic compound of claim 10, wherein A₃is an X₃-containing 5-membered ring or an X₃-containing 5-membered ringto which at least one 6-membered ring is condensed, and A₄ is anX₄-containing 5-membered ring, an X₄-containing 5-membered ring to whichat least one 6-membered ring is condensed, or an X₄-containing6-membered ring.
 13. The organometallic compound of claim 10, wherein agroup represented by

in Formula 1 is a group represented by one of Formulae A1(1) to A1(32):

wherein in Formulae A1(1) to A1(32), X₁, T₁, and Y₁ are respectively thesame as described in connection with X₁, T₁, and Y₁ in Formula 1, R₁₁and R₁₂ are each independently the same as described in connection withR₁ in Formula 1, R₅₁ and R₅₂ are each independently the same asdescribed in connection with R₅ in Formula 1, b52 is an integer from 0to 2, b53 is an integer from 0 to 3, b54 is an integer from 0 to 4, R₁₁and R₁₂ are optionally bound to each other to form a C₃-C₆₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), two R₅₁(s) of at least two R₅₁(s) when b53 is 2 or greater areoptionally bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), two R₅₁(s) when b52 is 2 are optionally bound to each other toform a C₃-C₆₀ carbocyclic group unsubstituted or substituted with atleast one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted orsubstituted with at least one R_(10a), two R₅₂(s) of at least two R₅₂(s)when b54 is 2 or greater are optionally bound to each other to form aC₃-C₆₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), two R₅₂(s) of at least two R₅₂(s) when b53 is 2 orgreater are optionally bound to each other to form a C₃-C₆₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), R_(10a) is the same as described in connection with R_(10a) inFormula 1, * indicates a binding site to M in Formula 1, *′ indicates abinding site to T₄ in Formula 1, and *″ indicates a binding site to A₂in Formula
 1. 14. The organometallic compound of claim 10, wherein agroup represented by

in Formula 1 is a group represented by one of Formulae A2-1 to A2-8:

wherein in Formulae A2-1 to A2-8, X₂ is the same as described inconnection with X₂ in Formula 1, X₂₁ to X₂₃ are each independently thesame as described in connection with X₂ in Formula 1, R₂₁ to R₂₃ areeach independently the same as described in connection with R₂ inFormula 1, and R₂₁ to R₂₃ are each not hydrogen, two of R₂₁ to R₂₃ areoptionally bound to each other to form a C₃-C₆₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), R_(10a) is the same as described in connection with R_(10a) inFormula 1, * indicates a binding site to M in Formula 1, *′ indicates abinding site to T₂ in Formula 1, and *″ indicates a binding site to T₁in Formula
 1. 15. The organometallic compound of claim 10, wherein agroup represented by

in Formula 1 is a group represented by one of Formulae A3-1 to A3-15:

wherein in Formulae A3-1 to A3-15, X₃ is the same as described inconnection with X₃ in Formula 1, X₃₂ to X₃₇ are each independently thesame as described in connection with X₃ in Formula 1, R₃₁ to R₃₄ areeach independently the same as described in connection with R₃ inFormula 1, and R₃₁ to R₃₃ are each not hydrogen, b34 is an integer from0 to 4, two of R₃₁ to R₃₄ are optionally bound to each other to form aC₃-C₆₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), two R₃₄(s) of at least two R₃₄(s) when b34 is 2 orgreater are optionally bound to each other to form a C₃-C₆₀ carbocyclicgroup unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), R_(10a) is the same as described in connection with R_(10a) inFormula 1, * indicates a binding site to M in Formula 1, *″ indicates abinding site to T₂ in Formula 1, and *′ in Formulae A3-9 to A3-12 andA3-15 is a binding site to T₃ in Formula
 1. 16. The organometalliccompound of claim 10, wherein a group represented by

in Formula 1 is a group represented by one of Formulae A4-1 to A4-32:

wherein in Formulae A4-1 to A4-32, X₄ is the same as described inconnection with X₄ in Formula 1, X₄₁ to X₄₇ are each independently thesame as described in connection with X₄ in Formula 1, R₄₁ to R₄₅ areeach independently the same as described in connection with R₄ inFormula 1, and R₄₁ to R₄₃ are each not hydrogen, R₄₄ in Formulae A4-20,A4-25, A4-26, and A4-28 to A4-30 is not hydrogen, b43 is an integer from0 to 3, b44 is an integer from 0 to 4, two of R₄₁ to R₄₅ are optionallybound to each other to form a C₃-C₆₀ carbocyclic group unsubstituted orsubstituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic groupunsubstituted or substituted with at least one R_(10a), two R₄₄(s) of atleast two R₄₄(s) when b44 is 2 or greater are optionally bound to eachother to form a C₃-C₆₀ carbocyclic group unsubstituted or substitutedwith at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstitutedor substituted with at least one R_(10a), two R₄₅(s) of at least twoR₄₅(s) when b43 is 2 or greater are optionally bound to each other toform a C₃-C₆₀ carbocyclic group unsubstituted or substituted with atleast one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted orsubstituted with at least one R_(10a), R_(10a) is the same as describedin connection with R_(10a) in Formula 1, * indicates a binding site to Min Formula 1, *″ indicates a binding site to T₄ in Formula 1, and *′ inFormulae A4-9 to A4-12, A4-15, A4-31, and A4-32 is a binding site to T₃in Formula
 1. 17. The organometallic compound of claim 10, wherein CY₁is a Y₁-containing 5-membered ring, a Y₁-containing 5-membered ringcondensed to at least one 6-membered ring, or a Y₁-containing 6-memberedring.
 18. The organometallic compound of claim 10, wherein a grouprepresented by

in Formula 1 is a group represented by Formula CY1(a):

wherein in Formula CY1(a), Y_(1a) is C or N, CY₁₁ is a C₃-C₆₀carbocyclic group or a C₁-C₆₀ heterocyclic group, CY₁₂ is the same asdescribed in connection with CY₁ in Formula 1, R_(5a) and R_(5b) areeach independently the same as described in connection with R₅ inFormula 1, b5a and b5b are each independently the same as described inconnection with b5 in Formula 1, two R_(5a)(s) of at least two R_(5a)(s)when b5a is 2 or greater are optionally bound to each other to form aC₃-C₆₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), two R_(5b)(s) of at least two R_(5b)(s) when b5bis 2 or greater are optionally bound to each other to form a C₃-C₆₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a), R_(10a) is the same as described in connection withR_(10a) in Formula 1, *′ indicates a binding site to A₁ in Formula 1,and *″ indicates a binding site to T₁ in Formula
 1. 19. Theorganometallic compound of claim 10, wherein the organometallic compoundis selected from Compounds 1 to 105:


20. The organometallic compound of claim 10, wherein the organometalliccompound emits blue light having a maximum emission wavelength in arange of about 430 nanometers (nm) to about 490 nm.